ToolStripItem.OnPaint(PaintEventArgs) Méthode

Définition

Déclenche l'événement Paint.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)

Paramètres

e
PaintEventArgs

PaintEventArgs qui contient les données d'événement.A PaintEventArgs that contains the event data.

Exemples

L’exemple de code suivant montre comment substituer la OnPaint méthode pour un rendu personnalisé.The following code example demonstrates how to override the OnPaint method for custom rendering. Cet exemple de code fait partie d’un exemple plus complet fourni ToolStripItem pour la classe.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

Remarques

Le déclenchement d'un événement appelle le gestionnaire des événements par l'intermédiaire d'un délégué.Raising an event invokes the event handler through a delegate. Pour plus d’informations, consultez gestion et déclenchement d’événements.For more information, see Handling and Raising Events.

La méthode OnPaint permet également aux classes dérivées de gérer l'événement sans y attacher de délégué.The OnPaint method also allows derived classes to handle the event without attaching a delegate. Il s'agit de la méthode recommandée pour gérer l'événement dans une classe dérivée.This is the preferred technique for handling the event in a derived class.

Notes pour les héritiers

Lors de la substitution de OnPaint(PaintEventArgs) dans une classe dérivée, veillez à appeler la méthode OnPaint(PaintEventArgs) de la classe de base de manière à ce que les délégués inscrits reçoivent l'événement.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.

S’applique à