ToolStripItem.OnPaint(PaintEventArgs) Method

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

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

e: PaintEventArgs

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.

Applies to

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