Message Структура

Определение

Implements a Windows message.Implements a Windows message.

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

Примеры

В следующем примере кода показано переопределение метода WndProc для работы с сообщениями операционной системы, определенными в Message.The following code example demonstrates overriding the WndProc method to handle operating system messages identified in the Message. 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 значениях Message.Msg, Message.LParamи Message.WParam см. в документации по структуре сообщений.For information about the available Message.Msg, Message.LParam, and Message.WParam values, see the MSG Structure documentation. Сведения о фактических значениях констант см. в разделе константы сообщения.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

Комментарии

Структура Message создает оболочку для сообщений, которые отправляет Windows.The Message structure wraps messages that Windows sends. Эту структуру можно использовать для создания оболочки сообщения и назначения ее процедуре окна для отправки.You can use this structure to wrap a message and assign it to the window procedure to be dispatched. Эту структуру также можно использовать для получения сведений о сообщении, которое система отправляет в приложение или элементы управления.You can also use this structure to get information about a message the system sends to your application or controls. Дополнительные сведения о сообщениях Windows см. в разделе сообщения и очереди сообщений.For more information about Windows messages, see Messages and Message Queues.

Нельзя создать Message напрямую.You cannot create the Message directly. Вместо этого используйте метод Create.Instead, use the Create method. Для повышения эффективности Message использует пул существующих Messages вместо создания экземпляра нового, если это возможно.For the sake of efficiency, the Message uses its pool of existing Messages instead of instantiating a new one, if possible. Однако если Message недоступна в пуле, создается новый экземпляр.However, if a Message is not available in the pool, a new one is instantiated.

Свойства

HWnd

Gets or sets the window handle of the message.Gets or sets the window handle of the message.

LParam

Specifies the LParam field of the message.Specifies the LParam field of the message.

Msg

Gets or sets the ID number for the message.Gets or sets the ID number for the message.

Result

Specifies the value that is returned to Windows in response to handling the message.Specifies the value that is returned to Windows in response to handling the message.

WParam

Gets or sets the WParam field of the message.Gets or sets the WParam field of the message.

Методы

Create(IntPtr, Int32, IntPtr, IntPtr)

Creates a new Message.Creates a new Message.

Equals(Object)

Determines whether the specified object is equal to the current object.Determines whether the specified object is equal to the current object.

GetHashCode()

Returns the hash code for this instance.Returns the hash code for this instance.

GetLParam(Type)

Gets the LParam value and converts the value to an object.Gets the LParam value and converts the value to an object.

ToString()

Returns a String that represents the current Message.Returns a String that represents the current Message.

Операторы

Equality(Message, Message)

Determines whether two instances of Message are equal.Determines whether two instances of Message are equal.

Inequality(Message, Message)

Determines whether two instances of Message are not equal.Determines whether two instances of Message are not equal.

Применяется к

Дополнительно