Message Message Message Message Struct

Definizione

Implementa un messaggio di Windows.Implements a Windows message.

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

Esempi

Esempio di codice seguente viene illustrato l'override di WndProc metodo per gestire i messaggi di sistema operativo individuati nel Message.The following code example demonstrates overriding the WndProc method to handle operating system messages identified in the Message. Il sistema operativo WM_ACTIVATEAPP viene gestito in questo esempio per sapere quando un'altra applicazione sta diventando sempre attiva.The WM_ACTIVATEAPP operating system message is handled in this example to know when another application is becoming active. Per informazioni sui contatori Message.Msg, Message.LParam, e Message.WParam i valori, vedere il struttura MSG documentazione.For information about the available Message.Msg, Message.LParam, and Message.WParam values, see the MSG Structure documentation. Per informazioni sui valori di costante effettivi, vedere costanti messaggio.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
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 'Main

        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

Commenti

Il Message struttura include i messaggi da Windows invia.The Message structure wraps messages that Windows sends. È possibile usare questa struttura per il wrapping di un messaggio e assegnarlo alla routine della finestra deve essere inviato.You can use this structure to wrap a message and assign it to the window procedure to be dispatched. È anche possibile usare questa struttura per ottenere informazioni su un messaggio viene inviato dal sistema all'applicazione o controlli.You can also use this structure to get information about a message the system sends to your application or controls. Per altre informazioni sui messaggi di Windows, vedere i messaggi e le code di messaggi.For more information about Windows messages, see Messages and Message Queues.

Non è possibile creare il Message direttamente.You cannot create the Message directly. Usare invece il Create (metodo).Instead, use the Create method. A fini di efficienza, il Message utilizza il proprio pool esistente Messages anziché creare un'istanza di uno nuovo, se possibile.For the sake of efficiency, the Message uses its pool of existing Messages instead of instantiating a new one, if possible. Tuttavia, se un Message è non disponibile nel pool, viene creata una nuova.However, if a Message is not available in the pool, a new one is instantiated.

Proprietà

HWnd HWnd HWnd HWnd

Ottiene o imposta l'handle di finestra del messaggio.Gets or sets the window handle of the message.

LParam LParam LParam LParam

Specifica il campo LParam del messaggio.Specifies the LParam field of the message.

Msg Msg Msg Msg

Ottiene o imposta il numero di ID del messaggio.Gets or sets the ID number for the message.

Result Result Result Result

Specifica il valore restituito a Windows in risposta alla gestione del messaggio.Specifies the value that is returned to Windows in response to handling the message.

WParam WParam WParam WParam

Ottiene o imposta il campo WParam del messaggio.Gets or sets the WParam field of the message.

Metodi

Create(IntPtr, Int32, IntPtr, IntPtr) Create(IntPtr, Int32, IntPtr, IntPtr) Create(IntPtr, Int32, IntPtr, IntPtr) Create(IntPtr, Int32, IntPtr, IntPtr)

Crea un nuovo oggetto Message.Creates a new Message.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determina se l'oggetto specificato è uguale all'oggetto corrente.Determines whether the specified object is equal to the current object.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Restituisce il codice hash per l'istanza.Returns the hash code for this instance.

GetLParam(Type) GetLParam(Type) GetLParam(Type) GetLParam(Type)

Ottiene il valore LParam e lo converte in un oggetto.Gets the LParam value and converts the value to an object.

ToString() ToString() ToString() ToString()

Restituisce un oggetto String che rappresenta l'elemento Message corrente.Returns a String that represents the current Message.

Operatori

Equality(Message, Message) Equality(Message, Message) Equality(Message, Message) Equality(Message, Message)

Determina se due istanze di Message sono uguali.Determines whether two instances of Message are equal.

Inequality(Message, Message) Inequality(Message, Message) Inequality(Message, Message) Inequality(Message, Message)

Determina se due istanze di Message non sono uguali.Determines whether two instances of Message are not equal.

Si applica a

Vedi anche