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Docs: LCL/dbctrls. Adds and updates TDBCheckbox topics for changes in e27cc45f.
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@ -4572,8 +4572,15 @@ control:
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<element name="TDBCheckBox.SetValueUnchecked.AValue">
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<short>New value for the property.</short>
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</element>
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<element name="TDBCheckBox.NonDefaultValueChecked"/>
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<element name="TDBCheckBox.NonDefaultValueChecked.Result"/>
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<element name="TDBCheckBox.NonDefaultValueUnchecked"/>
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<element name="TDBCheckBox.NonDefaultValueUnchecked.Result"/>
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<element name="TDBCheckBox.CMGetDataLink">
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<short>Implements the CM_GETDATALINK control message for the data-aware
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<short>
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Implements the CM_GETDATALINK control message for the data-aware
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control.
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</short>
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<descr/>
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@ -4582,6 +4589,7 @@ control.
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<element name="TDBCheckBox.CMGetDataLink.Message">
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<short>Message examined and updated in the method.</short>
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</element>
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<element name="TDBCheckBox.GetFieldCheckState">
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<short>
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<var>GetFieldCheckState</var> - returns the checkbox state for the current
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@ -4590,13 +4598,16 @@ field.
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<descr>
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<p>
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<var>GetFieldCheckState</var> is a <var>TCheckBoxState</var> function used to
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get the current state for the checkbox. GetFieldCheckState uses the internal
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<var>TFieldDataLink</var> instance in the class to access the
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<var>Field</var> in the linked dataset represented by <var>DataField</var>.
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get the current value for the State property in the data-aware check box
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control. GetFieldCheckState uses the internal <var>TFieldDataLink</var>
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instance in the class to access the <var>Field</var> in the linked dataset represented by <var>DataField</var>.
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</p>
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<!-- HERE -->
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<p>
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The field value is examined to get the return value for the method. The
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return value can be one of the following:
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The field type and value are examined to determine the return value for the
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method. The return value can be one of the following:
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</p>
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<dl>
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<dt>cbChecked</dt>
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@ -4607,12 +4618,11 @@ Used when the Boolean value in the Field is <b>True</b>.
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<dd>
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Used when the Boolean value in the Field is <b>False</b>, or the String value
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matched ValueChecked. Also used when the Field has not been assigned
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(contains Nil).
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(contains <b>Nil</b>).
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</dd>
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<dt>cbGrayed</dt>
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<dd>
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Used when the value in Field is NULL, and when none of the previous
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conditions are <b>True</b>.
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Used when the value in Field is not NULL (depends on the database and the field type), and when none of the previous conditions are <b>True</b>.
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</dd>
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</dl>
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<p>
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@ -4625,6 +4635,7 @@ The return value is assigned to the <var>State</var> property when the
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<element name="TDBCheckBox.GetFieldCheckState.Result">
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<short>Current TCheckBoxState for the control.</short>
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</element>
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<element name="TDBCheckBox.DataChange">
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<short>
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Updates the control display value when the linked dataset is changed.
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@ -4633,38 +4644,50 @@ Updates the control display value when the linked dataset is changed.
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<p>
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<var>DataChange</var> is used to perform actions needed when the linked
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dataset for the control has been changed. In TDBCheckBox, this requires
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setting the
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<var>State</var> property for the control. DataChange calls the
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setting the <var>State</var> property for the control. DataChange calls the
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GetFieldCheckState method to get the value for the State property.
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</p>
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<p>
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DataChange is assigned as the <var>OnDataChange</var> event handler in the
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internal <var>TFieldDataLink</var> instance.
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DataChange is assigned in the constructor as the <var>OnDataChange</var>
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event handler in the internal <var>TFieldDataLink</var> instance for the
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control. It is temporarily unassigned (when used) prior to calling
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GetFieldCheckState, and reassigned prior to exit.
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</p>
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</descr>
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<seealso>
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<link id="TDBCheckBox.GetFieldCheckState"/>
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<link id="TDBCheckBox.State"/>
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<link id="TFieldDataLink.OnDataChange"/>
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</seealso>
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</element>
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<element name="TDBCheckBox.DataChange.Sender">
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<short>Object for the event notification.</short>
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</element>
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<element name="TDBCheckBox.DoOnChange">
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<short>Performs actions needed when the control is clicked.</short>
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<descr>
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<p>
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<var>DoOnChange</var> is an overridden method in <var>TDBCheckBox</var>. It
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ensures that the internal <var>TFieldDataLink</var> is notified of a change
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to the control value. The <var>Edit</var>, <var>Modified</var>, and
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<var>UpdateRecord</var> methods in the field data link are called to store
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the new value for the control. If the linked dataset cannot be edited, the
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<var>GetFieldCheckState</var> is called to get the value stored in the
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<var>State</var> property.
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to the control value.
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</p>
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<p>
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DoOnChange calls the inherited method prior to exit.
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If the OnDataChange event handler has been assigned for the field data link,
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its <var>Edit</var>, <var>Modified</var>, and <var>UpdateRecord</var> methods
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are called to store the new value for the control. If the linked dataset
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cannot be edited, the <var>GetFieldCheckState</var> method is called to get
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the checked state value stored to the <var>State</var> property.
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</p>
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<p>
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The OnDataChange event handler in the data link is temporarily unassigned
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proper to updating the field value. The handler is reassigned when the
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actions have been completed.
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</p>
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<p>
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DoOnChange calls the inherited method to signal the OnEditingDone and
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OnChange event handlers in ancestor classes.
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</p>
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<remark>
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No actions are performed in the method when the internal TFieldDataLink does
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not have an assigned <var>OnDataChange</var> event handler.
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</remark>
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</descr>
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<seealso>
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<link id="TDBCheckBox.State"/>
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@ -4743,28 +4766,50 @@ component is destroyed.
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<short>Constructor for the class instance.</short>
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<descr>
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<p>
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<var>Create</var> is the constructor for <var>TDBCheckBox</var>. It calls the
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inherited <var>Create</var> method, and forms the logical connections for
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checked and unchecked, sets initial style and state, forms datalinks and
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actions.
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<var>Create</var> is the constructor for <var>TDBCheckBox</var>, and calls
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the inherited constructor on entry.
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</p>
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<p>
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Create sets the default values for the ValueChecked and ValueUnchecked
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properties to the corresponding strings returned from the BoolToStr. ValueChecked is set to '-1'. ValueUnchecked is set to '0'. Change the values
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in ValueChecked and ValueUnchecked if other string representations are needed.
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</p>
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<p>
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The default value for the State property is set to cbUnchecked.
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</p>
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<p>
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Create allocates and configures the internal TFieldDataLink instance used to
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link the data-aware control to its Field in the underlying DataSource. The
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OnDataChange and OnUpdateData event handlers in the link are set to the
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DataChange and UpdateData methods in the control.
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</p>
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</descr>
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<seealso>
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<link id="TDBCheckBox.State"/>
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<link id="TDBCheckBox.ValueChecked"/>
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<link id="TDBCheckBox.ValueUnchecked"/>
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<link id="TDBCheckBox.DataChange"/>
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<link id="TDBCheckBox.UpdateData"/>
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<link id="TFieldDataLink"/>
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<link id="#lcl.stdctrls.TCustomCheckBox.Create">TCustomCheckBox.Create</link>
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<link id="#rtl.sysutils.BoolToStr">SysUtils.BoolToStr</link>
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</seealso>
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</element>
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<element name="TDBCheckBox.Create.TheOwner">
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<short>Owner of the class instance.</short>
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</element>
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<element name="TDBCheckBox.Destroy">
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<short>Destructor for the class instance.</short>
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<descr>
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<p>
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<var>Destroy</var> is the destructor for <var>TDBCheckBox</var>. It frees
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links and calls inherited <var>Destroy</var> method.
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the internal field data link, and calls the inherited <var>Destroy</var>
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method prior to exit.
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</p>
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</descr>
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<seealso>
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<link id="TFieldDataLink"/>
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<link id="#lcl.controls.TWinControl.Destroy">TWinControl.Destroy</link>
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</seealso>
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</element>
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@ -5052,27 +5097,125 @@ modified (doesn't make much sense for a check-box unless the box is
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<descr/>
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<seealso/>
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</element>
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<element link="#lcl.controls.TControl.ShowHint" name="TDBCheckBox.ShowHint"/>
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<element link="#lcl.controls.TWinControl.TabOrder" name="TDBCheckBox.TabOrder"/>
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<element link="#lcl.controls.TWinControl.TabStop" name="TDBCheckBox.TabStop"/>
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<element name="TDBCheckBox.ValueChecked">
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<short>
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<var>ValueChecked</var> is the value to use when the box is checked, for
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example
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<b>True</b> or 1.
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String representation for the check box value when the control is in its
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checked state.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>ValueChecked</var> is a <var>String</var> property with the value for
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the control when its State property contains the value cbChecked (or Checked
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is set to <b>True</b>). It is the string representation for the boolean
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value, like: 'True', '1', or -1'.
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</p>
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<p>
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The default value for the property is assigned in the constructor, and
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contains the value returned from BoolToStr(True). Changing the value for the
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property causes the DataChange method to be called. This updates the control
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State after the new property value has been assigned to its member.
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</p>
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<p>
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ValueChecked is not written using the LCL resource streaming mechanism if a
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non-default value has not been explicitly assigned to the property.
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</p>
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<p>
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ValueChecked is used in the GetFieldCheckState method when the control is
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linked to a field that is not a Boolean field type. It provides the value
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which is compared to the field value to determine the checked State for the
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control.
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</p>
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<p>
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ValueChecked is also used in the UpdateData method when the control is linked
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to field that is not a Boolean field type. It provides the value that is
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stored in the field when the Checked property is <b>True</b> (State is
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cbChecked).
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</p>
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<p>
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Use ValueUnchecked to specify the string used for the unchecked state in the
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control.
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</p>
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</descr>
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<version>
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Modified in version 2.4 to include the storage specifier for the property
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value.
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</version>
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<seealso>
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<link id="TDBCheckBox.Create"/>
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<link id="TDBCheckBox.State"/>
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<link id="TDBCheckBox.GetFieldCheckState"/>
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<link id="TDBCheckBox.DataChange"/>
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<link id="TDBCheckBox.UpdateData"/>
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<link id="TDBCheckBox.ValueUnchecked"/>
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<link id="#rtl.sysutils.BoolToStr">SysUtils.BoolToStr</link>
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<link id="#rtl.sysutils.TrueBoolStrs">SysUtils.TrueBoolStrs</link>
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</seealso>
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</element>
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<element name="TDBCheckBox.ValueUnchecked">
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<short>
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<var>ValueUnchecked</var> is the value to use when the box is unchecked, for
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example
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<b>False</b> or 0.
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String representation for the check box value when the control is in its
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unchecked state.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>ValueUnchecked</var> is a <var>String</var> property with the value for
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the control when its State property contains the value cbUnchecked (or
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Checked is set to <b>False</b>). It is the string representation for the
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boolean value, like: 'False' or '0'.
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</p>
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<p>
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The default value for the property is assigned in the constructor, and
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contains the value returned from BoolToStr(False). Changing the value for the
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property causes the DataChange method to be called. This updates the control
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State after the new property value has been assigned to its member.
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</p>
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<p>
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ValueUnchecked is not written using the LCL resource streaming mechanism if a
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non-default value has not been explicitly assigned to the property.
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</p>
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<p>
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ValueUnchecked is used in the GetFieldCheckState method when the control is
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linked to a field that is not a Boolean field type. It provides the value
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which is compared to the field value to determine the checked State for the
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control.
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</p>
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<p>
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ValueUnchecked is also used in the UpdateData method when the control is
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linked to field that is not a Boolean field type. It provides the value that
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is stored in the field when the Checked property is <b>False</b> (State is
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cbUnchecked).
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</p>
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<remark>
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The property value is not included in the LCL resource streaming mechanism if
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a non-default value has not been explicitly assigned to the property.
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</remark>
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<p>
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Use ValueChecked to specify the string used for the checked state in the
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control.
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</p>
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</descr>
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<version>
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Modified in version 2.4 to include the storage specifier for the property
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value.
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</version>
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<seealso>
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<link id="TDBCheckBox.Create"/>
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<link id="TDBCheckBox.State"/>
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<link id="TDBCheckBox.GetFieldCheckState"/>
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<link id="TDBCheckBox.DataChange"/>
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<link id="TDBCheckBox.UpdateData"/>
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<link id="TDBCheckBox.ValueChecked"/>
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<link id="#rtl.sysutils.BoolToStr">SysUtils.BoolToStr</link>
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<link id="#rtl.sysutils.TrueBoolStrs">SysUtils.TrueBoolStrs</link>
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</seealso>
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</element>
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<element name="TDBCheckBox.Visible">
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<short>
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Indicates if the control is visible on its parent.
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@ -8671,7 +8814,7 @@ DataSource is set to Nil when the component is freed.
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</element>
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<element name="TDBCalendar.Create">
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<short>
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Constructor for the class instance.
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Constructor for the class instance.
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</short>
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<descr>
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<p>
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@ -8694,7 +8837,7 @@ handlers in the TFieldDataLink instance.
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</element>
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<element name="TDBCalendar.Destroy">
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<short>
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Destructor for the class instance.
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Destructor for the class instance.
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</short>
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<descr>
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<p>
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