Message Struct

Definition

Implementa un mensaje de Windows.Implements a Windows message.

public value class Message
public struct Message
type Message = struct
Public Structure Message
Inheritance
Message

Examples

En el ejemplo de código siguiente se muestra cómo invalidar el método WndProc para controlar los mensajes del sistema operativo identificados en el Message.The following code example demonstrates overriding the WndProc method to handle operating system messages identified in the Message. En este ejemplo se trata el mensaje del sistema operativo WM_ACTIVATEAPP para saber cuándo se está activando otra aplicación.The WM_ACTIVATEAPP operating system message is handled in this example to know when another application is becoming active. Para obtener información sobre los valores de Message.Msg, Message.LParamy Message.WParam disponibles, consulte la documentación sobre la estructura MSG .For information about the available Message.Msg, Message.LParam, and Message.WParam values, see the MSG Structure documentation. Para obtener información sobre los valores constantes reales, consulte constantes de mensaje.For information about the actual constant values, see Message Constants.

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

Remarks

La estructura Message contiene los mensajes que envía Windows.The Message structure wraps messages that Windows sends. Puede usar esta estructura para ajustar un mensaje y asignarlo al procedimiento de ventana que se va a enviar.You can use this structure to wrap a message and assign it to the window procedure to be dispatched. También puede usar esta estructura para obtener información sobre un mensaje que el sistema envía a la aplicación o a los controles.You can also use this structure to get information about a message the system sends to your application or controls. Para obtener más información acerca de los mensajes de Windows, consulte mensajes y colasde mensajes.For more information about Windows messages, see Messages and Message Queues.

No se puede crear el Message directamente.You cannot create the Message directly. En su lugar, use el método Create.Instead, use the Create method. Por motivos de eficacia, el Message utiliza su grupo de Messages existentes en lugar de crear instancias de una nueva, si es posible.For the sake of efficiency, the Message uses its pool of existing Messages instead of instantiating a new one, if possible. Sin embargo, si una Message no está disponible en el grupo, se crea una instancia de una nueva.However, if a Message is not available in the pool, a new one is instantiated.

Properties

HWnd

Obtiene o establece el identificador de ventana del mensaje.Gets or sets the window handle of the message.

LParam

Especifica el campo LParam del mensaje.Specifies the LParam field of the message.

Msg

Obtiene o establece el número de Id. del mensaje.Gets or sets the ID number for the message.

Result

Especifica el valor que se devuelve a Windows en respuesta al control del mensaje.Specifies the value that is returned to Windows in response to handling the message.

WParam

Obtiene o establece el campo WParam del mensaje.Gets or sets the WParam field of the message.

Methods

Create(IntPtr, Int32, IntPtr, IntPtr)

Crea una Message nueva.Creates a new Message.

Equals(Object)

Determina si el objeto especificado es igual que el objeto actual.Determines whether the specified object is equal to the current object.

GetHashCode()

Devuelve el código hash para esta instancia.Returns the hash code for this instance.

GetLParam(Type)

Obtiene el valor de LParam y convierte el valor en un objeto.Gets the LParam value and converts the value to an object.

ToString()

Devuelve un valor de tipo String que representa la clase Message actual.Returns a String that represents the current Message.

Operators

Equality(Message, Message)

Determina si dos instancias de Message son iguales.Determines whether two instances of Message are equal.

Inequality(Message, Message)

Determina si dos instancias de Message no son iguales.Determines whether two instances of Message are not equal.

Applies to

See also