Data-Aware Grids to display and operate on information held in a database EInvalidGridOperation - exception class for invalid grid operatins TCustomDBGrid - the Base class for TDBGrid, a data-aware component for displaying information from a database in the manner of a Stringrid HowToUseDataAwareControls HowToUseGrids TColumn - one of the physical columns of the display in a DataBase Grid (not necessarily the same as a Column in a SQL database)

TColumn - one of the physical columns of the display in a DataBase Grid

Each column may display the information held in a Field of the DataSet to which the DBGrid is attached, but the order of appearance of the columns need not correspond to the order in which the Fields exist in the DataSet, nor need all Fields be represented by a Column.

TDataSetScrolledEvent - generic method for handling scrolling events in a DataSet TDBGridClickEvent - generic event handling method for a click in the specified column of a DataBase Grid TMovedEvent - generic event handler method for moving between FromIndex and ToIndex in a DataBase Grid TDrawColumnCellEvent - generic event handler method for drawing a cell in a specified column in a DataBase Grid TGetDbEditMaskEvent - generic event handler method for obtaining an Edit Mask in a DataBase Grid TDBGridOption - enumerated type, containing options available for a DataBase Grid TDbGridExtraOption - some extra options available for DataBase Grids TDbGridExtraOptions - set of TDbGridExtraOption TDbGridOptions - set of TDbGridOption TDbGridStatusItem - enumerated type containing items available for defining DataBase Grid status TDbGridStatus set of TDbGridStatusItem TDbGridSelEditorEvent - generic event handling method for selecting an Editor for a DataBase Grid TPrepareDbGridCanvasEvent - generic event handling method for preparing the Canvas for a DataBase Grid TBookmarkList - a list of Bookmarks in a DataBase Grid Create - constructor for TBookmarkList: calls inherited Create, attaches Grid and initialises list TObject.Create Destroy - destructor for TBookmarkList: clears and frees the list then calls inherited Destroy TObject.Destroy Clear the list of Bookmarks Delete the Bookmarks from the list one by one Find the nominated Bookmark string, returning its index; result (boolean) is True if successful IndexOf - returns the index of the nominated Bookmark string Refresh - searches for any invalid Bookmarks, which it removes: returns True if the action was successful Count - the number of Bookmarks in the list CurrentRowSelected - True if the current row is selected Items - the list of Bookmarks as an indexed array of strings TColumnOrder - enumerated type defining alternative ordering methods for the columns

TColumnOrder - enumerated type defining alternative ordering methods for the columns

Can be design order, or ordered by field index

TComponentDataLink - forms a link between a component and a DataSet and contains event handlers to operate on the records RecordChanged - calls the OnRecordChanged event handler if it has been assigned TDataLink.RecordChanged DataSetChanged - calls the OnDataSetChanged event handler if it has been assigned TDataLink.DataSetChanged ActiveChanged - if there has been a change in the Active status, calls the appropriate event handler for the change

ActiveChanged - if there has been a change in the Active status, calls the appropriate event handler for the change

May call one of the following:

OnNewDataSet
OnDataSetOpen
OnInvalidDataSet
OnDataSetClosed

TDataLink.ActiveChanged LayoutChanged - calls the OnLayoutChanged event handler if it is assigned TDataLink.LayoutChanged DataSetScrolled - calls the OnDataSetScrolled event handler if it is assigned TDataLink.DataSetScrolled EditingChanged - calls OnEditingChanged if it is assigned TDataLink.EditingChanged UpdateData - calls OnUpdataData event handler if it is assigned TDataLink.UpdateData Modified - True if the data have been modified OnRecordChanged - event handler for a change in the current record OnDataSetChanged - event handler for a change in the attached Data Set OnNewDataSet - event handler for formation of a link to a new data set OnDataSetOpen - event handler when the data set is open OnInvalidDataSet - event handler when the data set is non-valid OnInvalidDataSource - event handler when the data source is non-valid OnLayoutChanged - event handler when the layout of the data set has changed OnDataSetClose - event handler when the data set is closed OnDataSetScrolled - event handler when the data set is scrolled OnEditingChanged - event handler for a change in the Editing property OnUpdateData - event handler for implementing any pending changes to data DataSetName - the (string) name of the attached data set Fields - an indexed array containing the fields of the dataset TColumnTitle - class of TGridColumnTitle TColumn - one of the physical columns of the display in a DataBase Grid (not necessarily the same as a Column in a SQL database)

TColumn - one of the physical columns of the display in a DataBase Grid

Find which field's data is to be displayed in this column GetPickList - calls inherited GetPickList, then if there are additional items, adds them before returning TGridColumn.GetPickList Find which DataSet is to be used GetDefaultReadOnly - if a grid or field have been assigned, gets the default readonly property from the link, otherwise calls inherited GetDefaultReadOnly TGridColumn.GetDefaultReadOnly GetDefaultWidth - looks to see if a grid with canvas has been allocated, and gets width from there, otherwise uses global defaut width TGridColumn.GetDefaultWidth GetDisplayName - if a field has been assigned, return the nameof the field otherwise calls inherited GetDisplayName TCollectionItem.GetDisplayName LinkField - if the data link is Active, form the link with this feild Create - constructor for TColumn: calls inherited Create and sets a design index of appropriate size Create instantiates a new item in a TCollection. It is called by the TCollection.Add function and should under normal circumstances never be called directly. TGridColumn.Create Destroys this collection item.

Destroy removes the item from the managing collection and Destroys the item instance.

This is the only way to remove items from a collection;

The Field in the DataSet that is to be associated with this Column, for display , editinig etc Refers to the whole entity Field, including contents, name, position in the dataset, properties such as read/write enabling etc Assign - if the Source is a Grid, copies relevant values across, otherwise calls inherited Assign TPersistent.Assign GetDefaultAlignment - returns the supplied alignment if valid, otherwise returns the inherited default TGridColumn.GetDefaultAlignment GetDefaultDisplayFormat - returns a string containing the default format for display GetDefaultValueChecked - if the value of the checked item is boolean, returns the boolean expressed as a string TGridColumn.GetDefaultValueChecked GetDefaultValueUnchecked - if the value of the unchecked item is boolean, returns the boolean expressed as a string TGridColumn.GetDefaultValueUnchecked IsAutomaticColumn - if True, this is an automatic column IsDesignColumn - if True, this is a design column DesignIndex - the likely maximum index value The format to be used for display in this column The name of the field (as a string), as returned from the dataset TDBGridColumns - the columns of data found in a Database Grid Update - calls LayoutChanged if updates required TCollection.Update ColumnFromField - returns the column identity corresponding to the given field Add - first removes any autocolumns, then calls inherited Add TCollection.Add LinkFields - links all the fields to the corresponding items in the list of columns Items - the indexed array of Columns that hold the data in the Grid HasAutomaticColumns - checks through the list of columns, and if any one IsAutomaticColumn, returns True HasDesignColumns - checks through the list of columns, and if any one IsDesignColumn, returns True RemoveAutoColumns - goes through the list of columns and removes any that are automatic

RemoveAutoColumns - goes through the list of columns and removes any that are automatic

Only does this if HasAutomaticColumns is True

ResetColumnsOrder if coDesignOrder has been specified, rearrange the columns in the specified order TCustomDBGrid - the base class for TDBGrid , for displaying database information in the manner of a StringGrid HowToUseDataAwareControls HowToUseGrids UpdateData - implements any pending changes in the data: uses a method appropriate to the data type of the field GetDsFieldFromGridColumn - returns the identity of the DataSet field corresponding to the nominated grid column GetFieldFromGridColumn obtain the field either from a Db column or directly from dataset fields GetGridColumnFromField - obtain the corresponding grid column for the given field FieldIndexFromGridColumn returns the index for the database field corresponding to the stated grid column BeginLayout starts producing the layout for the grid CellClick - calls the OnCellClickevent handler if it is assigned for this particular cell CreateWnd - creates the window: calls inherited CreateWnd and adjusts layout if needed, in particular putting in scrollbars TWinControl.CreateWnd DefaultDrawCell - the default method for drawing a cell at the specified location, depending on the type of cell DoExit - closes down data links and calls inherited DoExit TWinControl.DoExit DoOnChangeBounds - calls inherited DoOnChangeBounds, adjusts layout if required TControl.DoOnChangeBounds EditingColumn - the Ok status is true if the data are being modified over the link EditorCancelEditing - cancels changes and disables editing processes EditorDoGetValue - calls inherited EditorDoGetValue and performs UpdateData TCustomGrid.EditordoGetValue EditorCanAcceptKey checks the integrity of the datalink and that the key and field are valid character entities TCustomGrid.EditorCanAcceptKey EndLayout - finishes modifying layout GetEditMask - checks datalink, finds field value and calls OnFieldEditMask if it is assigned TCustomGrid.GetEditMask GetEditText - checks the datalink, finds field and loads its text GridCanModify returns True if datalink is active and allows editing, and readonly is not set HeaderClick - calls OnHeaderClick if assigned TCustomGrid.HeaderClick KeyDown - checks key for a number of special cases, and calls the OnKeyDown event handler if assigned, otherwise calls inherited KeyDown LinkActive - if False, calls RemoveAutomaticColumns and LayoutChanged LayoutChanged - links columns to fields, inserts any required automatic columns MoveSelection - calls inherited MoveSelection and updates the Active state TCustomGrid.MoveSelection MouseDown - checks for a number of special cases and calls the OnMouseDown event handler, or calls inherited MouseDown UpdateActive - updates the Active status for the field and record UpdateGridCounts - modifies the total sizes allowing for any pending changes The DataSource from which this grid displays - usually the result of a database Query Set True to prevent writing to grid; set False to allow modification Event handler for mouse click in a cell of the grid Event handler if mouse enters column or it gains focus Event handler if mouse leaves column or it loses focus OnColumnMoved - event handler for moving a column Event handler if the cell in this column requires to be drawn Event handler if field is associated with an edit mask Event handler for mouse click on Title Create - constructor for TCustomDBGrid: calls inherited Create then sets up datalink events, options and defaults TCustomGrid.Create DefaultDrawColumnCell - the default method for drawing cells in this column TCustomGrid.Destroy Destroy - destructor for TCustomDbGrid: frees rows, frees the datalink, calls inherited Destroy The selected field, for editing, data input or simply viewing AddAutomaticColumns add as many columns as there are fields in the dataset; do this only at runtime. InvalidateSizes renders the Sizes non-valid ColumnEditorStyle - returns a button style appropriate to the kind of column being edited DoMouseWheelDown - calls the OnMouseWheelDown event handler if assigned, and adjusts position of pointer over the link TControl.DoMouseWheelDown DoMouseWheelUp - calls the OnMouseWheelUp event handler if assigned, and adjusts position of pointer over the link DoPrepareCanvas - calls the OnPrepareCanvas event handler if assigned TCustomGrid.DoPrepareCanvas DrawCheckboxBitmaps calls DrawGridCheckboxBitmaps after checking that datatype of relevant cell is boolean DrawFixedText draws the text in a fixed row GetBufferCount - returns the size of the buffer GetDefaultColumnAlignment - gets a default alignment from the stated column if it has one, otherwise supplies a default LeftJustify alignment GetDefaultColumnWidth - calls DefaultFieldColWidth (private function) GetDefaultColumnReadOnly - finds default ReadOnly status for column from data link GetDefaultColumnTitle - returns the display name from the nominated grid column GetDefaultRowHeight calls inherited GetDefaultRowHeight and makes it a little smaller TCustomGrid.GetDefaultRowHeight RemoveAutomaticColumns - strips out any automatic columns from the grid GridStatus - the status of the grid (whether updating, removing auto columns etc) OptionsExtra - the extra options for this grid OptionsExtra - the extra options for this grid: autocolumns and enable checkboxes SelectedRows - recorded as a bookmark list OnColumnSized - event handler for re-sizing a column OnPrepareCanvas - event handler for preparing canvas OnSelectEditor - event handler for selecting editor OnUserCheckboxBitmap - event handler: user-defined bitmap for checkboxes

OnUserCheckboxBitmap - event handler: user-defined bitmap for checkboxes

The user is encouraged to provide bitmaps to represent the three states for database grid checkboxes: gcbpUnChecked, gcbpChecked and gcbpGrayed

Initiate the action associated with this control ResetColWidths - restore the column widths to their default values Selected index - number of the row selected for viewing or editing The selected column for viewing or editing Columns and fields are often used interchangeably, but their properties are different. ThumbTracking - returns True if thumb tracking is used TdbGrid - a data-aware version of TStringGrid, for displaying and operating on a series of Rows and Columns from a database

TdbGrid - a data-aware version of TStringGrid, for displaying and operating on a series of Rows and Columns from a database

Inherits many of its properties from TCustomGrid and, of course, from TCustomDBGrid

HowToUseDataAwareControls HowToUseGrids The Canvas is the area of screen on which the various components are drawn.
This inherits its properties from TCanvas,
and that description should be read to understand their definitions more fully.

// standard properties, which should be supported by all descendants

Either reads a flag containing alignment instructions (FAlign) or writes alignment instructions (SetAlign)

May have no alignment, may have custom or client alignment, or can be aligned to top, bottom, left or right

// standard properties, which should be supported by all descendants

Determines how the control is to be anchored to its client or parent conrol

Either reads a flag containing the set of anchors to be used, or writes a set of anchors. If they have been written, this is indicated in IsAnchorsStored

Only a restricted series of options is available: none or a single border.

// standard properties, which should be supported by all descendants

Reads the value for colour, or stores the value, and sets a flag if the colour is stored.

The default colour is the same as the window in which the control is located.

Refers to the physical columns of the grid, displaying the contents of the relevant Fields

The Columns property is configurable from the Object Inspector by selecting the ellipsis (...) next to the property name, in which case a pop-up memo box appears to allow editing. It deals with things like the size, shape and format of the display, and contains a link to the appropriate Field.

Do no confuse Grid columns (in the display) with the SQL usage of COLUMNS, which corresponds to Fields in our environment. The Fields consist of a series of cells arranged in Records, which contain the actual data which are to be displayed and operated upon.

It is entirely possible that not all fields of the dataset are displayed, and so fields do not correspond directly to columns; in fact the Columns property allows the user to configure which data field is to be displayed in each column

// standard properties, which should be supported by all descendants

Determine Constraints (max and min height and width) for this control; reads the size constraints or stores new ones.

If new rows of the grid are created by changing the RowCount property, the height of these new rows will be set to the value of the DefaultRowHeight property.

After that the user may redefine this value. If the Options property includes the appropriate value, the row height may also be changed by the user at runtime.

// standard properties, which should be supported by all descendants

Whether the control is Enabled. If not, it usually appears 'greyed-out'

Reads a flag to see whether the control is enabled, or stores a new value. If stored, sets a flag to say so.

The color used by headings. // standard properties, which should be supported by all descendants
Reads the details of the pop-up menu, or stores them.
Properties are defined in the parent class TPopupMenu // standard properties, which should be supported by all descendants
Reads flag or writes one to determine if a hint is to be shown when mouse hovers over this control. If value is stored, a storage flag is set. Display of the actual hint is controlled by OnShowHint Reads or writes information in flag; default is -1

Reads or writes boolean flag; default is False

Use the TabStop to allow or disallow access to the control using the Tab key.

If TabStop is True, the control is in the tab order. If TabStop is False, the control is not in the tab order and the user can't use the Tab key to move to the control.

Visible - can the control be seen?

The Visible property represents the ability to see a visual control. 
          If Visible is True the control is shown, otherwise it is hidden.
          Calling Show sets, among others, Visible to True.
          Setting Visible to False is equivalent to calling Hide method.

The Visible property does not depend on control's parent visibility. Use IsVisible method to consider this and get real visibility.

Double-clicking is much more common in a Windows environment than in Unix or Linux, where single-clicking is the default method for selecting an object. However, in all environments there could be valid use for a double-click, and a method should be supplied if appropriate.

OnKeyDown - event handler for instance when key is down while control has focus

Differs from OnKeyPress in that the key may have already been down when the control received focus; with OnKeyPress the key needs to become pressed while the control has focus.

OnKeyPress - event controller for a key being pressed while the control has focus

Differs from OnKeyDown in that the key needs to become pressed while the control has focus; with OnKeyDown the key may have already been down when the control received focus.

OnKeyUp - event handler for instance when a key is up (not pressed) while the control has focus

The key may already have been up when the control received focus, or a pressed key may become released during the time the control has focus.

// standard properties, which should be supported by all descendants

Determines the border spacing for this control

Reads flag to find stored spacing values required for the border of the control, or writes the flag to set the spacing.

The properties are defined in the parent class TControlBorderSpacing

TBMStringList - a special StringList for BookMarks in a DataBase Grid IsValidChar - returns True if the supplied field contains a valid ASCII or UTF8 character