ComboBox.WndProc(Message) ComboBox.WndProc(Message) ComboBox.WndProc(Message) ComboBox.WndProc(Message) Method

Определение

Обрабатывает сообщения Windows.Processes Windows messages.

protected:
 override void WndProc(System::Windows::Forms::Message % m);
protected override void WndProc (ref System.Windows.Forms.Message m);
override this.WndProc : Message -> unit
Protected Overrides Sub WndProc (ByRef m As Message)

Параметры

m
Message Message Message Message

Сообщение Message Windows для обработки.The Windows Message to process.

Примеры

В следующем примере кода показано переопределение WndProc метода для работы с сообщениями операционной системы, определенными Message в структуре.The following code example demonstrates overriding the WndProc method to handle operating system messages identified in the Message structure. Сообщение операционной системы WM_ACTIVATEAPP обрабатывается в этом примере, чтобы выяснить, когда становится активным другое приложение.The WM_ACTIVATEAPP operating system message is handled in this example to know when another application is becoming active. Сведения о доступных Message.Msgзначениях, и Message.WParam см. в справочной документации http://msdn.microsoft.com/library по пакету SDK для Message.LParamплатформы, расположенной в библиотеке MSDN.Refer to the Platform SDK documentation reference located in the MSDN library at http://msdn.microsoft.com/library to understand the available Message.Msg, Message.LParam, and Message.WParam values. Фактические значения констант можно найти в файле заголовка Windows. h, который входит в комплект загрузки пакета Platform SDK (раздел Core SDK), который также доступен в библиотеке MSDN по http://msdn.microsoft.com/libraryадресу.Actual constant values can be found in the Windows.h header file included in the Platform SDK (Core SDK section) download, which is also available in the MSDN library at http://msdn.microsoft.com/library.

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Security::Permissions;

namespace csTempWindowsApplication1
{
   public ref class Form1: public System::Windows::Forms::Form
   {
   private:

      // Constant value was found in the "windows.h" header file.
      static const Int32 WM_ACTIVATEAPP = 0x001C;
      Boolean appActive;

   public:
      Form1()
      {
         appActive = true;
         this->Size = System::Drawing::Size( 300, 300 );
         this->Text = "Form1";
         this->Font = gcnew System::Drawing::Font( "Microsoft Sans Serif",18.0F,System::Drawing::FontStyle::Bold,System::Drawing::GraphicsUnit::Point,((System::Byte)(0)) );
      }


   protected:
      virtual void OnPaint( PaintEventArgs^ e ) override
      {
         
         // Paint a string in different styles depending on whether the
         // application is active.
         if ( appActive )
         {
            e->Graphics->FillRectangle( SystemBrushes::ActiveCaption, 20, 20, 260, 50 );
            e->Graphics->DrawString( "Application is active", this->Font, SystemBrushes::ActiveCaptionText, 20, 20 );
         }
         else
         {
            e->Graphics->FillRectangle( SystemBrushes::InactiveCaption, 20, 20, 260, 50 );
            e->Graphics->DrawString( "Application is Inactive", this->Font, SystemBrushes::ActiveCaptionText, 20, 20 );
         }
      }


      [SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
      virtual void WndProc( Message% m ) override
      {
         
         // Listen for operating system messages.
         switch ( m.Msg )
         {
            case WM_ACTIVATEAPP:
               
               // The WParam value identifies what is occurring.
               appActive = (int)m.WParam != 0;
               
               // Invalidate to get new text painted.
               this->Invalidate();
               break;
         }
         Form::WndProc( m );
      }

   };

}


[STAThread]
int main()
{
   Application::Run( gcnew csTempWindowsApplication1::Form1 );
}

using System;
using System.Drawing;
using System.Windows.Forms;

namespace csTempWindowsApplication1
{
    public class Form1 : System.Windows.Forms.Form
    {
        // Constant value was found in the "windows.h" header file.
        private const int WM_ACTIVATEAPP = 0x001C;
        private bool appActive = true;

        [STAThread]
        static void Main() 
        {
            Application.Run(new Form1());
        }
        
        public Form1()
        {
            this.Size = new System.Drawing.Size(300,300);
            this.Text = "Form1";
            this.Font = new System.Drawing.Font("Microsoft Sans Serif", 18F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
        }

        protected override void OnPaint(PaintEventArgs e) 
        {
            // Paint a string in different styles depending on whether the
            // application is active.
            if (appActive) 
            {
                e.Graphics.FillRectangle(SystemBrushes.ActiveCaption,20,20,260,50);
                e.Graphics.DrawString("Application is active", this.Font, SystemBrushes.ActiveCaptionText, 20,20);
            }
            else 
            {
                e.Graphics.FillRectangle(SystemBrushes.InactiveCaption,20,20,260,50);
                e.Graphics.DrawString("Application is Inactive", this.Font, SystemBrushes.ActiveCaptionText, 20,20);
            }
        }

	[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]
        protected override void WndProc(ref Message m) 
        {
            // Listen for operating system messages.
            switch (m.Msg)
            {
                // The WM_ACTIVATEAPP message occurs when the application
                // becomes the active application or becomes inactive.
                case WM_ACTIVATEAPP:

                    // The WParam value identifies what is occurring.
                    appActive = (((int)m.WParam != 0));

                    // Invalidate to get new text painted.
                    this.Invalidate();

                    break;                
            }
            base.WndProc(ref m);
        }
    }
}
Imports System.Drawing
Imports System.Windows.Forms

Namespace csTempWindowsApplication1

    Public Class Form1
        Inherits System.Windows.Forms.Form

        ' Constant value was found in the "windows.h" header file.
        Private Const WM_ACTIVATEAPP As Integer = &H1C
        Private appActive As Boolean = True

        <STAThread()> _
        Shared Sub Main()
            Application.Run(New Form1())
        End Sub

        Public Sub New()
            MyBase.New()

            Me.Size = New System.Drawing.Size(300, 300)
            Me.Text = "Form1"
            Me.Font = New System.Drawing.Font("Microsoft Sans Serif", 18.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        End Sub

        Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)

            ' Paint a string in different styles depending on whether the
            ' application is active.
            If (appActive) Then
                e.Graphics.FillRectangle(SystemBrushes.ActiveCaption, 20, 20, 260, 50)
                e.Graphics.DrawString("Application is active", Me.Font, SystemBrushes.ActiveCaptionText, 20, 20)
            Else
                e.Graphics.FillRectangle(SystemBrushes.InactiveCaption, 20, 20, 260, 50)
                e.Graphics.DrawString("Application is Inactive", Me.Font, SystemBrushes.ActiveCaptionText, 20, 20)
            End If
        End Sub
	<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
        Protected Overrides Sub WndProc(ByRef m As Message)
            ' Listen for operating system messages
            Select Case (m.Msg)
                ' The WM_ACTIVATEAPP message occurs when the application
                ' becomes the active application or becomes inactive.
            Case WM_ACTIVATEAPP

                    ' The WParam value identifies what is occurring.
                    appActive = (m.WParam.ToInt32() <> 0)

                    ' Invalidate to get new text painted.
                    Me.Invalidate()

            End Select
            MyBase.WndProc(m)
        End Sub
    End Class
End Namespace

Комментарии

Все сообщения отправляются в WndProc метод после получения фильтрации PreProcessMessage с помощью метода.All messages are sent to the WndProc method after getting filtered through the PreProcessMessage method.

Метод WndProc точно соответствует функции WindowProc Windows.The WndProc method corresponds exactly to the Windows WindowProc function. Дополнительные сведения об обработке сообщений Windows см WindowProc . в документации по функциям в справочнике по Windows Platform SDK, расположенной в библиотеке MSDN по адресу. http://msdn.microsoft.com/libraryFor more information about processing Windows messages, see the WindowProc function documentation in the Windows Platform SDK reference located in the MSDN library at http://msdn.microsoft.com/library.

Примечания для тех, кто наследует этот метод

Наследуемые элементы управления должны вызывать WndProc(Message) метод базового класса для обработки любых сообщений, которые не обрабатываются.Inheriting controls should call the base class's WndProc(Message) method to process any messages that they do not handle.

Безопасность

SecurityPermission
для наследования классов для вызова неуправляемого кода.for inheriting classes to call unmanaged code. Связанное перечисление: UnmanagedCode.Associated enumeration: UnmanagedCode.

Применяется к

Дополнительно