ToolStripItem.OnPaint(PaintEventArgs) Method

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Source:

ToolStripItem.cs

Raises the Paint event.

C#

protected virtual void OnPaint(System.Windows.Forms.PaintEventArgs e);

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.

C#

// 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);
    }
}

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