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Docs: LCL/imglist. Adds or updates TCustomImageList topics for changes in 79f7f1bb.

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* Adds: MarkAsChanged, DoAfterUpdateStarted, DoBeforeUpdateEnded
* Updates: BeginUpdate, EndUpdate
This commit is contained in:
dsiders 2023-06-20 01:24:02 +01:00
parent 91c776aade
commit 71dc7b718b
1 changed files with 152 additions and 10 deletions
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162
docs/xml/lcl/imglist.xml
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@ -1843,7 +1843,7 @@ resolution is not found using the specified image width.
<p>
<var>Index</var> is an output parameter used to store the ordinal position of
the image resolution that uses the specified image width. Index contains the
closest (but larger) resolution when the return value is <b>False</b>.
closest (but larger) resolution when the return value is <b>False</b>.
</p>
</descr>
</element>
@ -3295,6 +3295,121 @@ ClearOverlays is used in the implementation of the <var>Clear</var> and
</seealso>
</element>
<element name="TCustomImageList.MarkAsChanged">
<short>
Sets the value in the internal Changed flag to <b>True</b>.
</short>
<descr>
<p>
<var>MarkAsChanged</var> allows an application to set the value for the
internal member which tracks whether the image list has been modified. When
enabled, the Change method performs change notifications for subscribers and
signals the OnChange event handler (when assigned) when the EndUpdate method
is called.
</p>
<p>
MarkAsChanged sets the value for the internal member to <b>True</b>. This
update normally occurs in methods like Clear, Delete, Move, ReadData,
ReadAdvData, and when the value in BkColor is changed. MarkAsChanged allows
descendent classes to set the flag value from any methods added to the class
or from application code.
</p>
</descr>
<version>
Added in LCL version 2.4.0.
</version>
<seealso>
<link id="TCustomImageList.BeginUpdate"/>
<link id="TCustomImageList.EndUpdate"/>
<link id="TCustomImageList.BkColor"/>
<link id="TCustomImageList.Change"/>
<link id="TCustomImageList.Clear"/>
<link id="TCustomImageList.Delete"/>
<link id="TCustomImageList.Move"/>
<link id="TCustomImageList.OnChange"/>
<link id="TCustomImageList.ReadAdvData"/>
<link id="TCustomImageList.ReadData"/>
<link id="TChangeLink.Change"/>
<link id="TChangeLink.OnChange"/>
</seealso>
</element>
<element name="TCustomImageList.DoAfterUpdateStarted">
<short>
Performs actions needed after the BeginUpdate method is started.
</short>
<descr>
<p>
<var>DoAfterUpdateStarted</var> is a virtual method in
<var>TCustomImageList</var> called from the BeginUpdate method after the
internal update counter has been incremented. It is called when the first
update becomes active for the image list (the update counter is 1). Subsequent
calls to BeginUpdate do not call the DoAfterUpdateStarted method until the
update count returns to 1.
</p>
<p>
DoAfterUpdateStarted has an empty implementation in TCustomImageList, but can
be overridden in descendent classes to perform any actions needed in the
derived class.
</p>
<p>
Use DoBeforeUpdateEnded to perform actions needed in the EndUpdate method
prior to decrementing the update counter and calling the Change method.
</p>
<p>
Use MarkAsChanged to set the internal flag which tracks modifications to the
image list.
</p>
</descr>
<version>
Added in LCL version 2.4.0.
</version>
<seealso>
<link id="TCustomImageList.BeginUpdate"/>
<link id="TCustomImageList.EndUpdate"/>
<link id="TCustomImageList.DoBeforeUpdateEnded"/>
<link id="TCustomImageList.MarkAsChanged"/>
</seealso>
</element>
<element name="TCustomImageList.DoBeforeUpdateEnded">
<short>
Performs actions needed before the EndUpdate method is completed.
</short>
<descr>
<p>
<var>DoBeforeUpdateEnded</var> is a virtual method in
<var>TCustomImageList</var> called from the EndUpdate method. It is called
when the first update for the image list is completed (the update counter is
1). Subsequent calls to BeginUpdate do not call the DoAfterUpdateStarted
method until the update count returns to 1. It occurs immediately before the
update counter is decremented and the Change method is called.
</p>
<p>
DoBeforeUpdateEnded has an empty implementation in TCustomImageList, but can
be overridden in descendent classes to perform any actions needed in the
derived class.
</p>
<p>
Use DoAfterUpdateStarted to perform actions needed in the BeginUpdate method
after the update counter has been incremented.
</p>
<p>
Use MarkAsChanged to set the internal flag which tracks modifications to the
image list.
</p>
</descr>
<version>
Added in LCL version 2.4.0.
</version>
<seealso>
<link id="TCustomImageList.BeginUpdate"/>
<link id="TCustomImageList.EndUpdate"/>
<link id="TCustomImageList.DoAfterUpdateStarted"/>
<link id="TCustomImageList.MarkAsChanged"/>
</seealso>
</element>
<element name="TCustomImageList.Create">
<short>
Constructor for the class instance.
@ -3824,30 +3939,44 @@ identical content.
<element name="TCustomImageList.BeginUpdate">
<short>
Starts an update to the image list, and blocks execution of the OnChange
Starts an update to the image list, and controls execution of the OnChange
event.
</short>
<descr>
<p>
Use <var>BeginUpdate</var> when an update to the image list is started to
block execution of the OnChange event handler.
Call <var>BeginUpdate</var> when an update to the image list is started to
control execution of the OnChange event handler in Change.
</p>
<p>
<var>BeginUpdate</var> is used, along with <var>EndUpdate</var>, to speed up
the insertion of images in an image list. Every call to BeginUpdate must be
matched by a call to EndUpdate; i. e. update operations can be nested.
the insertion or modification of images in an image list. Every call to
BeginUpdate must be matched by a call to EndUpdate; i. e. update operations
can be nested.
</p>
<p>
BeginUpdate increments an internal counter in the class instance each time
the method is called. EndUpdate decrements the internal counter when called.
When the counter contains a positive non-zero value, the OnChange event
handler is not executed when the image list is changed.
the method is called. The DoAfterUpdateStarted method is called to perform any
actions needed in the image list when an update is started. It is called when
the internal counter is set to 1; subsequent calls to BeginUpdate do not call
DoAfterUpdateStarted until the update count has returned to 1.
</p>
<p>
EndUpdate is used to perform action needed when an update is completed and to
decrement the internal update counter. When the counter contains a positive
non-zero value, the OnChange event handler is not executed when the image list
is changed.
</p>
</descr>
<version>
Modified in LCL version 2.4.0 to call the DoAfterUpdateStarted method.
</version>
<seealso>
<link id="TCustomImageList.EndUpdate"/>
<link id="TCustomImageList.OnChange"/>
<link id="TCustomImageList.Change"/>
<link id="TCustomImageList.MarkAsChanged"/>
<link id="TCustomImageList.DoAfterUpdateStarted"/>
<link id="TCustomImageList.DoBeforeUpdateEnded"/>
</seealso>
</element>
@ -3864,7 +3993,7 @@ updates by blocking execution of the <var>OnChange</var> event handler.
<p>
BeginUpdate increments an internal counter in the class instance each time
the method is called. EndUpdate decrements the internal counter when called.
When the counter contains a positive non-zero value, the OnChange event
If the modified counter contains a positive non-zero value, the OnChange event
handler is not executed when the image list is changed. When the counter
reaches zero (<b>0</b>), the Change method is called to perform OnChange
notifications.
@ -3875,11 +4004,24 @@ method would cause the internal counter to contain a negative value, the
<var>RaiseGDBException</var> method is called to raise an exception for the
condition.
</p>
<p>
EndUpdate calls the DoBeforeUpdateEnded method to perform any actions needed
when the internal update counter is set to 1. The value in the internal
counter is decremented, and the Change method is called prior to exit. Change
notifications and the OnChange event handler occur when there are no other
nested BeginUpdate calls active.
</p>
</descr>
<version>
Modified in LCL version 2.4.0 to call the DoBeforeUpdateEnded method.
</version>
<seealso>
<link id="TCustomImageList.BeginUpdate"/>
<link id="TCustomImageList.Change"/>
<link id="TCustomImageList.OnChange"/>
<link id="TCustomImageList.DoBeforeUpdateEnded"/>
<link id="TCustomImageList.DoAfterUpdateStarted"/>
<link id="TCustomImageList.MarkAsChanged"/>
</seealso>
</element>