- The property SimpleText can be assigned programmatically to display the value of some variable, such as the position of the Splitter in the example. + The property SimpleText can be assigned in code to display the value of some variable, such as the position of the Splitter in the example.
- OnDrawPanel is an event handler used to draw the specified panel on the status bar. OnDrawPanel is signalled (when assigned) from the DrawPanel method. Assign an object procedure using the signature in TDrawPanelEvent to render the specified panel to the desired rectangle in the status bar. + OnDrawPanel is an event handler used to draw the specified panel on the status bar. OnDrawPanel is signalled (when assigned) from the DrawPanel method. Assign an object procedure using the signature in TDrawPanelEvent to render the specified panel to the desired rectangle in the status bar.
- The Options property must contain the value nboKeyboardTabSwitch to enable the tab switching feature. Pressing Ctrl+Tab switches to the next page by incrementing the PageIndex value. Pressing Ctrl+Shift+Tab switches to the previous page by decrementing the PageIndex value. + The Options property must contain the value nboKeyboardTabSwitch to enable the tab switching feature. Pressing Ctrl+Tab switches to the next page by incrementing the PageIndex value. Pressing Ctrl+Shift+Tab switches to the previous page by decrementing the PageIndex value.
If Key is not the VK_TAB virtual key code, the inherited method is called to handle the values in Key and Shift. @@ -3192,7 +3192,7 @@ ImagesWidth specifies the width used for the Images in the control. ImagesWidth determines the resolution (either selected or resized) for the current display density (PPI).
- Changing the value in the property causes the DoImageListChange method to be called to select the image resolution, and to notify the widgetset class of the change. The UpdateTabProperties method is called to propogate the change to all tabs in the control. + Changing the value in the property causes the DoImageListChange method to be called to select the image resolution, and to notify the widgetset class of the change. The UpdateTabProperties method is called to propagate the change to all tabs in the control.
- SetTabHeight is used to set the height for the tabs displayed on the control to the value in AValue. SetTabHeight calls GetCapabilities to determine if the value nbcTabsSizeable is included in the capabilties for the control. No actions are performed in the method when nbcTabsSizeable is not present in the controls capabilities list. + SetTabHeight is used to set the height for the tabs displayed on the control to the value in AValue. SetTabHeight calls GetCapabilities to determine if the value nbcTabsSizeable is included in the capabilities for the control. No actions are performed in the method when nbcTabsSizeable is not present in the controls capabilities list.
SetTabHeight propogates the new tab height to the Notebook which contains the Tabs in the control.
@@ -5306,7 +5306,7 @@
- DisplayRect is a read-only TRect property which contains the display area for the page in the tabbed control. It uses the client rectangle for the control as the value for the property. Use TabRect to get the display area for the tab in the tabbed control.
+ DisplayRect is a read-only TRect property which contains the display area for the page in the tabbed control. It uses the client rectangle for the control as the value for the property. Use TabRect to get the display area for the tab in the tabbed control.
- Assign is an overridden method used copy property values from the persistent object in ASource into the current class instance. When ASource is a TListItem descendant, the following property values are copied:
+ Assign is an overridden method used copy property values from the persistent object in ASource into the current class instance. When ASource is a TListItem descendant, the following property values are copied:
- ColClick - procedure to simulate the OnColumnClick event. Can be used programmatically to execute the same code as is used to respond to the OnColumnClick event.
+ ColClick - procedure to simulate the OnColumnClick event. Can be used in code to execute the same code as is used to respond to the OnColumnClick event.
- Handles an F2 function key pressed when the control has focus. Ensures that the editor is displayed when the control is not marked as ReadOnly. The keystroke is digested (set to zero).
+ Handles an F2 function key pressed when the control has focus. Ensures that the editor is displayed when the control is not marked as ReadOnly. The keystroke is digested (set to zero).
If the control is marked as ReadOnly, or Key is not the unshifted F2 function key, the inherited KeyDown method is called to handle the values in Key and Shift.
@@ -9763,7 +9763,7 @@
The default value for the property is clDefault. Please note that the default value for ParentColor is True, and causes the color defined for the TCoolBar control to be used.
@@ -15549,7 +15548,7 @@
+ Create is the overridden constructor for TCustomTrackBar, and calls the inherited method on entry.
+
+ Create sets the default values for properties and members in the class instance, including the component and control style flags. The initial bounds for the control are set to the values from the GetControlClassDefaultSize method.
+
+ Tickmarks indicates where the ticks appear relative to the slider in the track bar control.
+
+ TTVChangedEvent is an object procedure type which specifies an event handler signalled when a node has been changed in a TCustomTreeView / TTreeView control.
+
+ Sender is the TObject instance for the change notification event.
+
+ Node is the TTreeNode instance that has been modified.
+
+ TTVChangedEvent is the type used for the TCustomTreeView.OnChange property.
+
+ TTVNodeChangedEvent is an object procedure type which specifies an event handler signalled when values in a tree node have been changed.
+
+ Sender contains the tree view control for the change notification.
+
+ Node is the TTreeNode instance with the modified value.
+
+ ChangeReason is a TTreeNodeChangeReason enumeration value that indicates the property changed in the tree node.
+
+ TTVNodeChangedEvent is the type used for the TCustomTreeView.OnNodeChanged property.
+
- A TTreeNode is part of a TTreeView and is used for storing data. This can be done by using the Caption property or for more complex data the Data property can be used. Each node can have sibling or child items associated with it.
+ A TTreeNode is part of a TTreeView and is used to store the data displayed in the control. This can be done by using the Text property or for more complex data the Data property can be used. Each node can have sibling or child items associated with it.
+ Calls the NodeChanged method in the associated TreeView control.
+
+ The return value contains the TTreeNodes container which owns the class instance.
+
+ Destroy is the overridden destructor for TTreeNode.
+
+ It notifies the owner ( the TTreeNodes container) that the tree node and its accessibility object are being deleted. The Unbind method is called to remove any references to the node in the parent and sibling nodes, or as a selection in TreeNodes.
+
+ Child nodes are removed by setting HasChildren to False. Child nodes in Items are freed, and its storage is set to Nil.
+
+ The Pointer in the Data property is set to Nil.
+
+ Destroy calls the inherited method prior to exit.
+
+ Calls the CustomSort method to perform the default sort algorithm (alphabetic).
+
+ The return value is the result from the CustomSort method, and contains True on success.
+
+ Bottom is an Integer function used to get the vertical coordinate for the bottom of the tree node. The return value is calculated as the sum of the Top and Height properties.
+
+ BottomExpanded is an Integer function used to get the bottom coordinate for the node subtree when it is expanded.
+
+ If the tree node has a visible sibling, the value in its Top property is used as the return value. When a sibling node does not exist, the bottom coordinate for the last visible and expanded child node is used. If the current node does not have child nodes, the value in the Bottom property is used as the return value.
+
- The child nodes (not the grand children) are sorted. If SortProc is nil the method DefaultTreeViewSort is used. The default implementation always returns true.
+ The child nodes (but not the grand-children) are sorted. If SortProc is Nil the method DefaultTreeViewSort is used. The default implementation always returns True.
+ EditText is a Boolean function used to start editing the Text for the tree node in the associated TreeView control. The return value is True when TreeView has been assigned and the value tvsIsEditing is present in the States property for the tree view control.
+
+ EditText calls the BeginEditing method in TreeView to configure, display, and activate the editor for the node.
+
+ Use EndEdit to close and optionally cancel the editing process in the associated TreeView control.
+
+ FindNode is a TTreeNode function used to get the child node with the text specified in NodeText.
+
+ FindNode examines the child nodes found in the Items property for the class instance. The GetFirstChild method is called to get the first child node in Items. Each tree node in Items is examined after calling GetNextSibling until a node with the requested value is located. The return value is the TTreeNode instance with a Text property that matches the value in NodeText, or Nil if a tree node is not found.
+
+ Use methods in the TTreeNodes container to locate tree nodes not in the current subtree; i. e. FindNodeWithText or FindNodeWithTextPath.
+
+ GetFirstChild is a TTreeNode function used to get the first child node in the subtree for the current tree node. GetFirstChild returns the first TTreeNode instance stored in the Items property (index position 0). The return value is Nil if Items is empty (Count is 0).
+
+ Use GetFirstVisibleChild to get the first child node with its Visible property set to True.
+
+ Use GetFirstSibling, GetNextSibling, GetPrevSibling, or GetLastSibling to retrieve a tree node at the same level in the tree hierarchy.
+
+ GetFirstVisibleChild is a TTreeNode function used to get the tree node that is the first visible child node in the subtree.
+
+ GetFirstVisibleChild calls GetFirstChild to retrieve the first child node in Items. If the first child node is not visible, each of the TTreeNode instances in Items is examined after calling GetNextVisibleSibling.
+
+ The return value is the first TTreeNode instance with its Visible property set to True. The return value is Nil if no visible child node was found in Items.
+
+ Use GetLastVisibleChild to retrieve the last visible child node in Items.
+
+ GetHandle is a THandle function used to get the value for the Handle property. It is the Handle allocated for the associated TreeView control.
+
+ GetNextVisible is a TTreeNode function used to get the next visible node for the current tree node.
+
+ If the current tree node is Expanded and Visible, the next node is the first visible child node. Otherwise, the next visible sibling node is used as the next node. If a sibling node does not exist, the Parent is searched for a visible sibling (next visible ancestor?).
+
+ The return value is Nil if a visible node is not found using the preceding logic, or when none of the ancestor nodes are visible and expanded.
+
+ The return value is -1 if the tree node in AValue is not a child node (its Parent node is not the current class instance). Calls GetIndex to calculate the position of the child node relative to previous sibling nodes. Roughly equivalent to calling IndexOf in the Items container, but using a TTreeNode search value instead of a String.
+
+
+
+
+ Delete is a method used to remove the tree node from the TTreeNodes container. Delete calls Free to destroy the object instance if the Deleting property is not set to True. No actions are performed when Deleting is True. +
++ Calls the ExpandItem method to implement the expansion and optional recursion. +
++ Calls the EnsureNodeIsVisible method in the associated TreeView (when assigned). Otherwise, calls the ExpandParents method. +
++ Cut is a Boolean property which indicates if the tree node has been cut from the tree structure. The property value is True when nsCut has been included in the States property for the tree node. Changing the value for the property causes the States property to be updated to include or exclude the node state value. +
++ Data is a Pointer property with a pointer to the custom data for the node. Data can contain any arbitrary data type, and must be cast to the correct types when used in an application. +
++ Setting a new value for the property causes the associated TreeView (when assigned) to sort the parent node or all of the TreeNodes when needed and allowed. It is needed when the tree view uses SortType stData or stBoth. It is allowed if the node is not being deleted and is bound to other tree nodes (States). +
++ The Changed method is called with the ncDataChanged node change reason. +
+ Deleting is a read-only Boolean property which indicates is the node is marked for deletion. Its value is True when ndDeleting has been included in the States property for the node. nsDeleting is added to States in the Destroy method, and indicates that the node will be freed. The Delete method in the TreeView control is called to signal an OnDeletion event (when assigned) before references for the node are removed and the TreeNodes are refreshed. It prevents the Delete method from being executed more than once. +
++ DropTarget is a Boolean property which indicates if the node is a drop target in a drag and drop operation. The value for the property is True when nsDropHilited has been included in the States property. +
++ Setting a new value for the property causes States to be updated to reflect the new value. When set to True, nsDropHilited is included in State and the internal last drop target is updated in the associated TreeView control. When set to False, nsDropHilited is excluded from States and the last drop target is set to Nil in the TreeView control. +
++ Expanded is a Boolean property which indicates if the node has been expanded in the associated TreeView control. The property value is True when nsExpanded has been included in the States property. +
++ The Expand method is called when the new value for the property is True. Otherwise, the Collapse method is called. States is updated in the Expand and Collapse methods. +
++ Focused is a Boolean property which indicates if the node has focus in the associated TreeView control. The value for the property is True when nsFocused has been included in the States property. +
++ Setting a new value for the property causes the values in States to be updated. When set to True, nsFocused is included in States. When set to False, nsFocused is excluded from States. The Update method is called to force the TreeView control to be redrawn. +
++ THandle is a read-only THandle property with the handle assigned for the associated TreeView control. The property value is 0 (zero) if a handle has not been assigned for the TreeView control. +
++ HasChildren is a Boolean property which indicates whether the tree node has child nodes. +
++ The property value is True when States includes the value nsHasChildren. Items is not used to determine the property value. +
++ Setting a new value for the property causes States to be updated to include or exclude nsHasChildren to reflect the new value. When the value is False, child nodes in the Items property are freed. +
++ The Update method is called to refresh the associated TreeView control (when assigned). +
++ Height is an Integer property with the height for the node including its text, images, and indicators. +
++ Height uses a default value if it contains 0 (zero) or a negative integer value. If an associated TreeView control has been assigned, the value in its DefaultItemHeight property is used as the property value. If TreeView in unassigned, the value in the DefaultTreeNodeHeight constant is used. +
++ Setting a new value for the property causes the States property in the associated TreeView control to be updated (when assigned). The values tvsScrollbarChanged and tvsTopsNeedsUpdate are included in the control States. The Update method is called to force the TreeView to be redrawn. The Changed method is called with the ncHeightChanged node change reason. +
++ Height is used along with Top to calculate the return value for the Bottom method. It is also used in the implementation of methods like DisplayRect and DisplayExpandSignRect. +
++ ImageIndex is an Integer property with the ordinal position for the image displayed for the node. It refers to a bitmap stored in the Images property of the associated TreeView control. The default value for the property is -1, and indicates that an image has not been assigned. +
++ Setting a new value for the property causes the Update method to be called to redraw the associated tree view control. The Changed method is called with the ncImageIndex node change reason. +
++ IsFullHeightVisible is a read-only Boolean property which indicates if the entire tree node is visible in the display area for the associated TreeView control. +
++ The IsNodeHeightFullVisible method in TreeView is called to get the value for the property. If the TreeView control has not been assigned, the AreParentsExpandedAndVisible method is used to get the return value. +
++ IsFullHeightVisible is used in the SelectionVisible method in TCustomTreeView when MultiSelect has not been enabled for the tree view control. +
++ IsVisible is a read-only Boolean property which indicates if the tree node is visible in the associated TreeView control. IsVisible is True if the node can be seen in the display area for the control. The property value is False when an ancestor node is collapsed (not Expanded). +
++ The IsNodeVisible method in TreeView is called to get the value for the property. If TreeView has not been assigned, the AreParentsExpandedAndVisible method is called to get the property value. +
++ IsNodeVisible is used in the Repaint method in TTreeNodes, and in the SelectionVisible method in TCustomTreeView. +
++ Items is an indexed TTreeNode property which provides access to the child nodes for the current node by their ordinal position. ItemIndex contains the ordinal position for the tree node instance, and must be in the range 0..Items.Count-1. An ETreeNodeError exception is raised if ItemIndex is not in the range needed for the Items property. +
++ Items is the default property for the class instance. +
++ Storing a new value to the indexed property causes the Assign method in the TTreeNode instance to be called to copy the properties values. +
++ Level is a read-only Integer property which contains the level in the tree structure for the node. It indicates the number of ancestor nodes in the structure, and implies the indentation for the node in the tree view control. +
++ The root of the tree is level 0. The value for the property is determined by counting the number of Parent nodes for each TTreeNode instance in the tree starting at the current node. +
++ Owner is a read-only TTreeNodes property with the container that owns the current TTreeNode instance. +
++ Parent is a read-only TTreeNode property which contains the parent node for the current tree node. +
++ Use Items to access and maintain the child nodes for the current tree node. +
++ Selected is a Boolean property which indicates the current node is selected in the associated TreeView control. The property value is True when nsSelected or nsMultiSelected has been included in the States property. nsSelected indicates that the node is assigned to the TCustomTreeView.Selected property. nsMultiSelected indicates that the node is stored in the the TCustomTreeView.Selections property when it has MultiSelect enabled. +
++ Setting a new value for the property causes the values in States to be updated. Similarly, the TreeView control is updated to used the node in the Selected or Selections property. +
++ The Update method is called to force the TreeView control to be redrawn. +
++ SelectedIndex is an Integer property with the ordinal position for the image displayed when the node is Selected. It refers to a bitmap in the Images property for the TreeView control, and allows an alternate image to be displayed for the node when it is selected. The default value is -1 and indicates that an image index has not been assigned. +
++ Changing the value in the property causes the Update method to be called to redraw the associated TreeView control. The Changed method is called with the ncSelectedIndex node change reason. +
++ Use ImageIndex to set the ordinal position for the image displayed when the tree node is not selected. +
++ States is a read-only TNodeStates properties which contains active state flags for the tree node. TNodeState enumeration values are included in or excluded from the set type as needed in methods for the tree node, the TreeNodes container, and the associated TreeView control. +
++ Text is a String property which contains the text displayed as the caption for the tree node. +
++ Changing the value in the property causes the TreeView control to be updated. Its States property is modified to include the value tvsMaxRightNeedsUpdate, which causes the node sizes to be recalculated and the control to be re-displayed. +
++ If the SortType for the TreeView is set to stText or stBoth, the Parent node is re-sorted. If the TreeView has not been assigned, the TreeNodes container is re-sorted. +
++ The Changed method is called with the ncTextChanged node change reason. +
++ Top is a read-only Integer property with the vertical coordinate for the top of the tree node. Top contains an Y-axis offset where the tree node is located in the display area for the associated TreeView control. +
++ The property value is calculated by calling the UpdateAllTops method in the TreeView control. The value contains the accumulated Height for all preceding TreeNodes starting at the first visible node in the control, and reflects their Visible and Expanded settings. The value is calculated in UpdateAllTops when tvsTopsNeedsUpdate has been included in the States property for the TreeView control. +
++ Use Height to get height for the text, images, and indicators used in a tree node. Use Bottom to get the vertical coordinate for the bottom of the tree node. +
++ TreeNodes is a read-only TTreeNodes property with the container where the tree node is stored, and the owner of the TTreeNode instance. TreeNodes provides properties and methods needed to store, access, and maintain the tree nodes for the TreeView control. TreeNodes is a reference to the Items property found in TreeView. +
++ The property value is Nil if Owner has not been assigned or is not derived from TTreeNodes. +
++ TreeView is a read-only TCustomTreeView property with the tree view control where the tree node and other nodes in TreeNodes are displayed. It is a reference to the Owner assigned to the TreeNodes property. +
++ TreeView provides access to the properties, methods, and events in the control. It is used to get the position for the node in the display area for the control. It is also notified when property values in the node are changed. +
++ Use TreeNodes to access the TTreeNode instances stored in TreeView. +
++ Visible is a Boolean property which indicates if the tree node is visible in the associated TreeView control. Its value is True when nsVisible has been included in the States property for the tree node. The default value for the property is True. +
++ Setting a new value for the property causes the States property to be udpated. Selected is set to False when the value in Visible is changed. +
++ Values are included in the States property for the associated TreeView control (when assigned) to indicate that the size and layout for the tree nodes in the control have been changed. The Update method is called to force the control to be refreshed. The Changed method is called with the ncVisibility node change reason. +
++ Create is the constructor for the class instance, and calls the inherited method on entry. Create stores the value in ANodes in the TTreeNodes member. Creates set the default value for the internal position counter used in the class instance. +
++ MoveNext is a Boolean function which indicates if another tree node is available to the enumerator. MoveNext increments the internal position counter for the enumerator. The return value is True if the position counter is less than the number of entries in the internal TTreeNodes container (in the range 0..TTreeNodes.Count-1). +
++ Use Current to access the TTreeNode instance when MoveNext returns True. +
++ Use MoveNext to navigate to the first or subsequent TTreeNode instance for the enumerator. Raises an exception if Current is accessed before the MoveNext method is called to retrieve the first value for the enumerator. +
++ TTreeNodes is a TPersistent descendant which implements a container used to store TTreeNode instances. TTreeNodes provides properties and methods used to create, store, access, and maintain nodes with a hierarchical tree structure. +
++ The indexed Item property provides access to the nodes in the container by their ordinal position. An enumerator can also be used to access tree nodes in the container. +
++ TTreeNodes is the type used for the Items property in TCustomTreeView. +
++ Create is the constructor for the class instance, and calls the inherited method on entry. Create allocates resources for the internal selection list in the class instance. The value in AnOwner is stored in the Owner property. +
++ Destroy is the overridden destructor for the class instance. Destroy calls Clear to remove TTreeNode instances stored in Item and values in the internal cache. The selection list for the class instance is also cleared, and its allocated resources are freed. Destroy calls the inherited method prior to exit. +
++ Returns the TTreeNode instance found which matches the text ancestry in TextPath, or Nil if a tree node is not found matching the specified values. +
++ TextPath contains the delimited text values used to locate a tree node. The '/' (Slash) character is used as the delimiter between text values in TextPath. An initial slash character representing the root node is not needed or allowed. The search always starts at the top-level tree nodes in the container. The FindNode method is used to locate subsequent delimited text values in TextPath. +
++ Raises an ETreeNodeError exception if AIndex is not a valid ordinal position in the internal selection list. AIndex must be in the range 0..SelectionCount-1. +
++ MultiSelect is a method used add nodes to the internal selection list relative to the node specified in Node. MultiSelect uses values in the MultiSelectStyle property for the tree view control in Owner to determine the nodes added. Specifically: +
++ ClearWholeSelection indicates whether all existing nodes in the multi-selection are cleared before added new node(s) to the selection list. When set to True, the ClearMultiSelection method is called. Otherwise, the last node in the selection list is removed. +
++ Nodes in the internal selection list are visited to set their MultiSelected property to True. Members used to track the first and last nodes in the multi-selection are updated prior to exit. +
+- Change is called from the event handler used for the internal timer activated when a new selection is made and the control synchronizes the tree nodes to the visual display. + Change is called from the event handler used for the internal timer activated when a new selection is made and the control synchronizes the tree nodes to the visual display.
Use the OnSelectionChange event handler for the notification that occurs before the node is included in the control selection.
@@ -20544,7 +20660,7 @@
- DoPaint is a method used render the control to its canvas. It Implements the overridden Paint method. No actions are performed in the method when tvsPainting has been included in the States property (Paint has already been called).
+ DoPaint is a method used render the control to its canvas. It Implements the overridden Paint method. No actions are performed in the method when tvsPainting has been included in the States property (Paint has already been called).
DoPaint includes the value tvsPainting in the States property to indicate that the paint method is active. It includes the value tvoFocusedPainting in States when Focused is True, or excludes the value when Focused is False.
@@ -21634,7 +21750,7 @@
CustomSort calls BeginUpdate to minimize updates during the sorting process. EndUpdates is called when the sorting process is completed.
- Top level nodes in Items are sorted by calling the SortTopLevelNodes in items. Child nodes are then sorted (when present), starting at the first top-level node in the tree. The ClearCache method in Items is called to invalidate the node cache for the control.
+ Top-level nodes in Items are sorted by calling the SortTopLevelNodes in items. Child nodes are then sorted (when present), starting at the first top-level node in the tree. The ClearCache method in Items is called to invalidate the node cache for the control.
The States property is updated to force the node coordinates and scrollbars to be refreshed in the control.
@@ -22321,7 +22437,7 @@ AText := ATreeView.Items.Item[0].Text; // caption for the first tree node
Selected is a TTreeNode property which contains the selected tree node in the control. A tree node is selected when the Left or Right mouse button is clicked on the code. It can also be selected by assigning a TTreeNode instance to the property.
- When a tree node is selected or unselected, the Selected property in the TTreeNode instance is updated. Use the OnChanging event handler to determine if a specific tree node can become the selected node in the control. Use the OnChange event handler to perform actions needed after the tree node is made the Selected node in the control.
+ When a tree node is selected or unselected, the Selected property in the TTreeNode instance is updated. Use the OnChanging event handler to determine if a specific tree node can become the selected node in the control. Use the OnChange event handler to perform actions needed after the tree node is made the Selected node in the control.
Selecting a tree node forces it to become fully visible in the control. This includes expanding parent nodes to ensure that the node is visible. The OnExpanding and OnExpanded event handlers are signalled before and after actions to a given tree node.
@@ -22761,25 +22877,46 @@ OldExpanded.Free;
+ THeaderSectionState is the type used to implement the THeaderSection.State property.
+
+ THeaderSection is a TCollectionItem descendant which implements a section displayed on a TCustomHeaderControl / THeaderControl instance. THeaderSection is the type added and maintained in the THeaderSections collection, and used in the TCustomHeaderControl.Sections property.
+
+ THeaderSection has properties which identify its visual characteristics. This includes the text displayed for the section, its alignment, minimum and maximum widths, and an index for an optional image. Other properties contain run-time information about the section, including its left and right coordinates and its display state.
+
+ THeaderSection instances are normally created at design-time and edited using the IDE object inspector. They can be created at run-time using methods in the THeaderSections collection, and edited in code.
+
+ Create is the overridden constructor for THeaderSection, and + calls the inherited Create method on entry. The value in ACollection is used as the Owner of the collection item. Create sets the default values for properties in the class instance. +
++ THeaderSections is a TCollection descendant used to store sections defined for a TCustomHeaderControl instance. THeaderSections is the type used to implement the Sections property in TCustomHeaderControl. +
++ THeaderSections re-implements methods from the ancestor class that are used to add, insert, delete, and retrieve THeaderSection instances stored in the collection. +
+- Update is an overridden method used to notify observers of a change to the specified item in the collection. + Update is an overridden method used to update the section in the header control. When Item is assigned, the UpdateSection method in the THeaderControl instance is called. If Item is unassigned (contains Nil), the UpdateSections method in the THeaderControl instance is called update all sections in the collection.
+ The THeaderSection instance in Item is created when the argument value is Nil (unassigned). The return value contains the new header section instance, or the existing value in Item when it is assigned. +
++ Items is an indexed THeaderSection property which provides access to the header sections in the collection by their ordinal position. It is implemented using TFpList to store the collection items. Items is the default property for the class instance. +
++ When reading a value in the property, the item is cast to the THeaderSection type used in the collection. SetItem is called to store a value for the indexed property. +
+- THeaderControl offers a widget that could be placed along the edge of a Panel or Form allowing a highly customized mechanism for selection. However there are no intrinsically associated display areas and it is the developer's responsibility to supply an index associated with the selection from the THeaderControl and determining what action is to occur or what is to be displayed in any attached Panel or Form. + THeaderControl offers a widget that could be placed along the edge of a Panel or Form allowing a highly customized mechanism for selection. However, there are no intrinsically associated display areas and it is the developer's responsibility to supply an index associated with the selection from the THeaderControl and determining what action is to occur or what is to be displayed in any attached Panel or Form.
+ Signals the OnSectionClick event handler (when assigned). Called from the Click method when the mouse event occurred on the header section in the Section argument. +
++ Signals the OnSectionResize event handler (when assigned). Called from the MouseUp method when mouse tracking has been ended for the specified Section. +
++ Signals the OnSectionTrack event handler (when assigned). Called from the MouseDown, MouseMove, and MouseUp methods when mouse tracking is active for a section in the header control. +
++ Signals the OnSectionSeparatorDblClick event handler (when assigned). Called from the DblClick method when the mouse event occurs when mouse tracking has been enabled for the header control. +
++ Create is the overridden constructor for TCustomHeaderControl, and calls the inherited Create on entry. +
++ Create allocates resources needed for the Sections property by call CreateSections. It also sets the default size for the control using the values returned from GetControlClassDefaultSize. +
++ The control style flags are updated in the method to include mouse capture and click events and to remove caption display for the control. +
++ Destroy is the overridden destructor for TCustomHeaderControl. It ensures that resources allocated to the Sections property are freed, and calls the inherited method prior to exit. +
++ GetSectionAt is an Integer function used to get the position for the header section found at the coordinates in P. +
++ GetSectionAt iterates over the THeaderSection instances in Sections to find a matching collection item. A match is found when the X- axis coordinate in P is within the Left and Right values for the header section. +
++ The return value contains the ordinal position in Sections where the header section is stored, or -1 if a header section was not found for the coordinates. +
++ Paint is an overridden method in TCustomHeaderControl used to draw the control to its Canvas. +
++ Paint calls the inherited method on entry to signal the OnPaint event handler (when assigned). The display rectangle is updated to reflect the current Width and Height for the control. +
++ Paint iterates over the header sections defined in the Sections property, and calls PaintSection to render each one. If all sections fit within the control display area without scrolling, theme services are used to draw the control to the control to its Canvas. +
++ Paint handles configuring the Canvas and drawing the preview when a section drag operation is in effect. +
++ See PaintSection for more information about the actions performed to draw an individual header section for the control. +
++ PaintSection is a method used to paint the specified header section to the Canvas for the THeaderControl control. +
++ Index contains the ordinal position for the THeaderSection instance in the Sections collection. No actions are performed in the method if the header section is not Visible. +
++ PaintSection draws the header section using the Left and Right properties in the THeaderSection instance. The value in its State property is used to render the section by calling methods in ThemeServices. When Images have been assigned in the control, and the header section has an assigned image index, it is drawn to the Canvas. When Text contains a non-empty value, it is also rendered to the Canvas using the DrawText method in ThemeServices. +
++ ChangeScale is an overridden method in TCustomHeaderControl, and calls the inherited method on entry to scale the overall size for the control and its child controls. ChangeScale applies the scaling factor represented by M and D to the individual header sections defined in the Sections collection. The Width for each THeaderSection instance is updated using the multiplier and divisor to scale the section width. +
++ The control cannot display images on the header section if Images has not been assigned or is empty. +
++ Use the ImageIndex property for the THeaderSection instances in Sections to assign the image used for the header section. +
++ If ImagesWidth is unassigned (contains 0), the width of the bitmaps in Images is used. +
++ Sections is a THeaderSections property with the collection of header sections defined for the control. The THeaderSection instances in the collection contain the size, layout, content, appearance, and state for each header section. +
++ SetColor is an overridden method in TCustomFrame used to set the value for the Color property. It calls the inherited method on entry. +
++ When the Color property contains a value other than clDefault, the ParentBackground property is set to False. +
+- The write access specifier is overridden in TCustomFrame, and calls the UpdateOpaque method. + The write access specifier is overridden in TCustomFrame. It calls the inherited method on entry. +
++ If the new property value is True and ParentColor is True, the color assigned to the Parent control is stored in the Color property. Otherwise, Color is set to the value clDefault. The UpdateOpaque method is called to adjust the control style flags for the control.
The default value for the property is True.
+ Changes the value in ParentBackground to False when Color is set to a value other than clDefault. +
+- The write access specifier is overridden in TCustomGroupBox, and calls the UpdateOpaque method. + The write access specifier is overridden in TCustomGroupBox. It calls the inherited method on enty. +
++ If AParentBackground is True and ParentColor is True, the Color from the Parent control is assigned to the Color property. Otherwise, the value clDefault is stored in the Color property. +
++ The UpdateOpaque method is called to adjust the control style flags in the control.
The default value for the property is True.