how define event with delegate

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VS2008

I want to know that how to call event with delegate.
My code is

In file1.cs //this main file I have to go through using EacApi

C#

namespace Program1
   {
     private StatusEventHandler OnGetCamStatus;
     [ComSourceInterfaces("Program1.IEacApiEvents")]
     [ClassInterface(ClassInterfaceType.None)]
     [ComVisible(true)]
     [Guid("ED8211C0-50A6-4873-8964-31A381D96A23")]
     public class EacApi
     {
         public event StatusEventHandler OnGetStatus
       {
         [MethodImpl(MethodImplOptions.Synchronized)] add
         {
           this.OnGetStatus = this.OnGetStatus + value;
         }
         [MethodImpl(MethodImplOptions.Synchronized)] remove
         {
           this.OnGetStatus = this.OnGetStatus - value;
         }
       }
   }
   }

In file2.cs

C#

 namespace Program1
    {
      public delegate void StatusEventHandler(int iType, int iValue, int iDataSize, object data);
    }
In file3.cs

        namespace Program1
    {
      [ComVisible(true)]
      [Guid("5D3FB90D-E41F-4412-B3D4-D6B7939E5214")]
      [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
      public interface IEacApiEvents
      {
        [DispId(3)]
        void OnGetCamStatus(int iType, int iValue, int iDataSize, object vData);
        }
        }

Posted 31-May-13 2:08am

Member 7909353

Updated 31-May-13 2:12am

NotPolitcallyCorrect

v2

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Sergey Alexandrovich Kryukov · Answer 1 · 2013-05-31T02:42:00

There is no such thing as "call a delegate". A delegate instance is invoked, which is a very different things: all the handlers from its invocation list get called. This is done like this:

C#

if (OnGetStatus != null)
    OnGetStatus.Invoke(this, new StatusEventArgs(/*...*/)); // or whatever is required by the signature of StatusEvenHandler

You can invoke this event only in this class (declared class), nowhere else, which is an important fool-proof feature.

Here, I made up the type StatusEvenArgs assuming that you are using the common event declaration pattern:

C#

class StatusEventArgs : System.EventArgs { /* ... specific event args parameters are defined in this class */ }

//...

public class EacApi {
   public event System.EventHandler<StatusEventArgs> OnGetStatus;
   //...
}

If you are doing something else, resort to this pattern. If, by some reason, you want to invoke event somehow else you should… review your code design; it's now going to happen. If this is the case, better explain your ultimate goal, they I would, most likely, be able to suggest a solution.

—SA