ToolStripItem.OnPaint(PaintEventArgs) Method
Definition
Important
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Raises the Paint event.
protected:
virtual void OnPaint(System::Windows::Forms::PaintEventArgs ^ e);
protected virtual void OnPaint (System.Windows.Forms.PaintEventArgs e);
abstract member OnPaint : System.Windows.Forms.PaintEventArgs -> unit
override this.OnPaint : System.Windows.Forms.PaintEventArgs -> unit
Protected Overridable Sub OnPaint (e As PaintEventArgs)
Parameters
A PaintEventArgs that contains the event data.
Examples
The following code example demonstrates how to override the OnPaint method for custom rendering. This code example is part of a larger example provided for the ToolStripItem class.
// This method defines the painting behavior of the control.
// It performs the following operations:
//
// Computes the layout of the item's image and text.
// Draws the item's background image.
// Draws the item's image.
// Draws the item's text.
//
// Drawing operations are implemented in the
// RolloverItemRenderer class.
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
if (this.Owner != null)
{
// Find the dimensions of the image and the text
// areas of the item.
this.ComputeImageAndTextLayout();
// Draw the background. This includes drawing a highlighted
// border when the mouse is in the client area.
ToolStripItemRenderEventArgs ea = new ToolStripItemRenderEventArgs(
e.Graphics,
this);
this.Owner.Renderer.DrawItemBackground(ea);
// Draw the item's image.
ToolStripItemImageRenderEventArgs irea =
new ToolStripItemImageRenderEventArgs(
e.Graphics,
this,
imageRect );
this.Owner.Renderer.DrawItemImage(irea);
// If the item is on a drop-down, give its
// text a different highlighted color.
Color highlightColor =
this.IsOnDropDown ?
Color.Salmon : SystemColors.ControlLightLight;
// Draw the text, and highlight it if the
// the rollover state is true.
ToolStripItemTextRenderEventArgs rea =
new ToolStripItemTextRenderEventArgs(
e.Graphics,
this,
base.Text,
textRect,
this.rolloverValue ? highlightColor : base.ForeColor,
base.Font,
base.TextAlign);
this.Owner.Renderer.DrawItemText(rea);
}
}
' This method defines the painting behavior of the control.
' It performs the following operations:
'
' Computes the layout of the item's image and text.
' Draws the item's background image.
' Draws the item's image.
' Draws the item's text.
'
' Drawing operations are implemented in the
' RolloverItemRenderer class.
Protected Overrides Sub OnPaint(e As PaintEventArgs)
MyBase.OnPaint(e)
If (Me.Owner IsNot Nothing) Then
' Find the dimensions of the image and the text
' areas of the item.
Me.ComputeImageAndTextLayout()
' Draw the background. This includes drawing a highlighted
' border when the mouse is in the client area.
Dim ea As New ToolStripItemRenderEventArgs(e.Graphics, Me)
Me.Owner.Renderer.DrawItemBackground(ea)
' Draw the item's image.
Dim irea As New ToolStripItemImageRenderEventArgs(e.Graphics, Me, imageRect)
Me.Owner.Renderer.DrawItemImage(irea)
' If the item is on a drop-down, give its
' text a different highlighted color.
Dim highlightColor As Color = CType(IIf(Me.IsOnDropDown, Color.Salmon, SystemColors.ControlLightLight), Color)
' Draw the text, and highlight it if the
' the rollover state is true.
Dim rea As New ToolStripItemTextRenderEventArgs( _
e.Graphics, _
Me, _
MyBase.Text, _
textRect, _
CType(IIf(Me.rolloverValue, highlightColor, MyBase.ForeColor), Color), _
MyBase.Font, _
MyBase.TextAlign)
Me.Owner.Renderer.DrawItemText(rea)
End If
End Sub
Remarks
Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.
The OnPaint method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.
Notes to Inheritors
When overriding OnPaint(PaintEventArgs) in a derived class, be sure to call the base class's OnPaint(PaintEventArgs) method so that registered delegates receive the event.