Application.AddMessageFilter(IMessageFilter) 方法

public:
 static void AddMessageFilter(System::Windows::Forms::IMessageFilter ^ value);

public static void AddMessageFilter (System.Windows.Forms.IMessageFilter value);

static member AddMessageFilter : System.Windows.Forms.IMessageFilter -> unit

Public Shared Sub AddMessageFilter (value As IMessageFilter)

参数

示例

The following code example creates a message filter called TestMessageFilter. 此筛选器阻止与鼠标左键相关的所有消息。 在使用消息筛选器之前，必须提供接口的 IMessageFilter 实现。

// Creates a  message filter.
ref class TestMessageFilter: public IMessageFilter
{
public:
   [SecurityPermission(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::UnmanagedCode)]
   virtual bool PreFilterMessage( Message % m )
   {
      
      // Blocks all the messages relating to the left mouse button.
      if ( m.Msg >= 513 && m.Msg <= 515 )
      {
         Console::WriteLine( "Processing the messages : {0}", m.Msg );
         return true;
      }

      return false;
   }

};

// Creates a  message filter.
public class TestMessageFilter : IMessageFilter
{
    public bool PreFilterMessage(ref Message m)
    {
        // Blocks all the messages relating to the left mouse button.
        if (m.Msg >= 513 && m.Msg <= 515)
        {
            Console.WriteLine("Processing the messages : " + m.Msg);
            return true;
        }
        return false;
    }
}

' Creates a message filter.
<SecurityPermission(SecurityAction.LinkDemand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
Public Class TestMessageFilter
    Implements IMessageFilter

    <SecurityPermission(SecurityAction.Demand)> _
    Public Function PreFilterMessage(ByRef m As System.Windows.Forms.Message) _
    As Boolean Implements IMessageFilter.PreFilterMessage
        ' Blocks all the messages relating to the left mouse button.
        If ((m.Msg >= 513) And (m.Msg <= 515)) Then
            Console.WriteLine("Processing the messages : " & m.Msg)
            Return True
        End If
        Return False
    End Function
End Class

注解

使用消息筛选器防止引发特定事件或在将事件传递到事件处理程序之前对事件执行特殊操作。 消息筛选器对特定线程是唯一的。

若要防止调度消息， value 传递给此方法的参数实例必须使用代码重写 PreFilterMessage 该方法来处理消息。 该方法必须返回 false。

适用于