DrawItemEventHandler Delegado

Definición

Representa el método que controlará el evento DrawItem de un control ComboBox, ListBox, MenuItem o TabControl.Represents the method that will handle the DrawItem event of a ComboBox, ListBox, MenuItem, or TabControl control.

public delegate void DrawItemEventHandler(System::Object ^ sender, DrawItemEventArgs ^ e);
public delegate void DrawItemEventHandler(object sender, DrawItemEventArgs e);
type DrawItemEventHandler = delegate of obj * DrawItemEventArgs -> unit
Public Delegate Sub DrawItemEventHandler(sender As Object, e As DrawItemEventArgs)

Parámetros

sender
Object

Origen del evento.The source of the event.

e
DrawItemEventArgs

Objeto DrawItemEventArgs que contiene los datos del evento.A DrawItemEventArgs that contains the event data.

Herencia
DrawItemEventHandler

Ejemplos

En el ejemplo de código siguiente se muestra un menú con un elemento de menú dibujado por el propietario.The following code example demonstrates a menu with an owner-drawn menu item. En este ejemplo se AddHandler utiliza la instrucción AddressOf y el operador para designar un delegado para MenuItem.DrawItem controlar el evento.This example uses the AddHandler statement and the AddressOf operator to designate a delegate to handle the MenuItem.DrawItem event. Para ejecutar el ejemplo, péguelo en un formulario que importe los espacios de nombres System, System. Windows. Forms y System. Drawing.To run the example place paste it in a form that imports the System, System.Windows.Forms, and System.Drawing namespaces. Asegúrese de que todos los eventos estén asociados a sus métodos de control de eventos.Ensure all events are associated with their event-handling methods.

internal:
   // Declare the MainMenu control.
   System::Windows::Forms::MainMenu^ MainMenu1;

   // Declare MenuItem2 as With-Events because it will be user drawn.
   System::Windows::Forms::MenuItem^ MenuItem2;

private:
   void InitializeMenu()
   {
      
      // Create MenuItem1, which will be drawn by the operating system.
      MenuItem^ MenuItem1 = gcnew MenuItem( "Regular Menu Item" );
      
      // Create MenuItem2.
      MenuItem2 = gcnew MenuItem( "Custom Menu Item" );
      
      // Set OwnerDraw property to true. This requires handling the
      // DrawItem event for this menu item.
      MenuItem2->OwnerDraw = true;
      
      //Add the event-handler delegate to handle the DrawItem event.
      MenuItem2->DrawItem += gcnew DrawItemEventHandler( this, &Form1::DrawCustomMenuItem );
      
      // Add the items to the menu.
      array<MenuItem^>^temp0 = {MenuItem1,MenuItem2};
      MainMenu1 = gcnew MainMenu( temp0 );
      
      // Add the menu to the form.
      this->Menu = this->MainMenu1;
   }

   // Draw the custom menu item.
   void DrawCustomMenuItem( Object^ sender, DrawItemEventArgs^ e )
   {
      // Cast the sender to MenuItem so you can access text property.
      MenuItem^ customItem = dynamic_cast<MenuItem^>(sender);
      
      // Create a Brush and a Font to draw the MenuItem.
      System::Drawing::Brush^ aBrush = System::Drawing::Brushes::DarkMagenta;
      System::Drawing::Font^ aFont = gcnew System::Drawing::Font( "Garamond",10,FontStyle::Italic,GraphicsUnit::Point );
      
      // Get the size of the text to use later to draw an ellipse
      // around the item.
      SizeF stringSize = e->Graphics->MeasureString( customItem->Text, aFont );
      
      // Draw the item and then draw the ellipse.
      e->Graphics->DrawString( customItem->Text, aFont, aBrush, (float)e->Bounds.X, (float)e->Bounds.Y );
      e->Graphics->DrawEllipse( gcnew Pen( System::Drawing::Color::Black,2 ), Rectangle(e->Bounds.X,e->Bounds.Y,(System::Int32)stringSize.Width,(System::Int32)stringSize.Height) );
   }
// Declare the MainMenu control.
internal System.Windows.Forms.MainMenu MainMenu1;

// Declare MenuItem2 as With-Events because it will be user drawn.
internal System.Windows.Forms.MenuItem MenuItem2;


private void InitializeMenu()
{

    // Create MenuItem1, which will be drawn by the operating system.
    MenuItem MenuItem1 = new MenuItem("Regular Menu Item");

    // Create MenuItem2.
    MenuItem2 = new MenuItem("Custom Menu Item");

    // Set OwnerDraw property to true. This requires handling the
    // DrawItem event for this menu item.
    MenuItem2.OwnerDraw = true;

    //Add the event-handler delegate to handle the DrawItem event.
    MenuItem2.DrawItem += new DrawItemEventHandler(DrawCustomMenuItem);
    
    // Add the items to the menu.
    MainMenu1 = new MainMenu(new MenuItem[]{MenuItem1, MenuItem2});																													  

    // Add the menu to the form.
    this.Menu = this.MainMenu1;
}

// Draw the custom menu item.
private void DrawCustomMenuItem(object sender, 
    DrawItemEventArgs e)
{

    // Cast the sender to MenuItem so you can access text property.
    MenuItem customItem = (MenuItem) sender;

    // Create a Brush and a Font to draw the MenuItem.
    System.Drawing.Brush aBrush = System.Drawing.Brushes.DarkMagenta;
    Font aFont = new Font("Garamond", 10, 
        FontStyle.Italic, GraphicsUnit.Point);

    // Get the size of the text to use later to draw an ellipse
    // around the item.
    SizeF stringSize = e.Graphics.MeasureString(
        customItem.Text, aFont);

    // Draw the item and then draw the ellipse.
    e.Graphics.DrawString(customItem.Text, aFont, 
        aBrush, e.Bounds.X, e.Bounds.Y);
    e.Graphics.DrawEllipse(new Pen(System.Drawing.Color.Black, 2),
        new Rectangle(e.Bounds.X, e.Bounds.Y, 
        (System.Int32)stringSize.Width,
        (System.Int32)stringSize.Height));
}
' Declare the MainMenu control.
Friend WithEvents MainMenu1 As System.Windows.Forms.MainMenu

' Declare MenuItem2 as With-Events because it will be user drawn.
Friend WithEvents MenuItem2 As System.Windows.Forms.MenuItem


Private Sub InitializeMenu()

    ' Create MenuItem1, which will be drawn by the operating system.
    Dim MenuItem1 As New MenuItem("Regular Menu Item")

    ' Create MenuItem2.
    MenuItem2 = New MenuItem("Custom Menu Item")

    ' Set OwnerDraw property to true. This requires handling the
    ' DrawItem event for this menu item.
    MenuItem2.OwnerDraw = True

    'Add the event-handler delegate to handle the DrawItem event.
    AddHandler MenuItem2.DrawItem, New DrawItemEventHandler(AddressOf DrawCustomMenuItem)

    ' Add the items to the menu.
    MainMenu1 = New MainMenu(New MenuItem() {MenuItem1, MenuItem2})

    ' Add the menu to the form.
    Me.Menu = Me.MainMenu1
End Sub

' Draw the custom menu item.
Private Sub DrawCustomMenuItem(ByVal sender As Object, ByVal e As _
        System.Windows.Forms.DrawItemEventArgs)

    ' Cast the sender to MenuItem so you can access text property.
    Dim customItem As MenuItem = CType(sender, MenuItem)

    ' Create a Brush and a Font to draw the MenuItem.
    Dim aBrush As System.Drawing.Brush = System.Drawing.Brushes.DarkMagenta
    Dim aFont As New Font("Garamond", 10, FontStyle.Italic, _
        GraphicsUnit.Point)

    ' Get the size of the text to use later to draw an ellipse
    ' around the item.
    Dim stringSize As SizeF = e.Graphics.MeasureString( _
        customItem.Text, aFont)

    ' Draw the item and then draw the ellipse.
    e.Graphics.DrawString(customItem.Text, aFont, _
        aBrush, e.Bounds.X, e.Bounds.Y)
    e.Graphics.DrawEllipse(New Pen(System.Drawing.Color.Black, 2), _
        New Rectangle(e.Bounds.X, e.Bounds.Y, CInt(stringSize.Width), _
        CInt(stringSize.Height)))
End Sub

Comentarios

Cuando se crea un delegado DrawItemEventArgs, se identifica el método que controlará el evento.When you create a DrawItemEventArgs delegate, you identify the method that will handle the event. Para asociar el evento al controlador, se debe agregar una instancia del delegado al evento.To associate the event with your event handler, add an instance of the delegate to the event. Siempre que se produce el evento, se llama a su controlador, a menos que se quite el delegado.The event handler is called whenever the event occurs, unless you remove the delegate. Para obtener más información sobre los delegados de controladores de eventos, vea controlar y provocar eventos.For more information about event handler delegates, see Handling and Raising Events.

Métodos de extensión

GetMethodInfo(Delegate)

Obtiene un objeto que representa el método representado por el delegado especificado.Gets an object that represents the method represented by the specified delegate.

Se aplica a

Consulte también: