I am trying to use a delegate in an UI application where my main thread will be responsible for showing the progress bar of the upload being carried you in the background by the worker thread. I wanted to know if I can pass a delegate from one class to another as an argument in the constructor. I am trying to pass it as an argument in the constructor of another class and as expected it gives me an error that delegate is a keyword an identifier is expected. Can anyone please help me with this.
public delegate bool ProgressDelegate(string fileName, long size);
public Class1()
{
ProgressDelegate progressDel = new ProgressDelegate(UploadPro
Class2 class2 = new Class2(arg1, arg2, progressDel);
...
}
public static bool ProgressDelegate(string, long)
{
...
...
}
public class Class2
{
public Class2(arg1, arg2, delegate progressDel)
{
...
...
}
...
...
}
If this is not the right way to do then how can I pass a delegate from one class to another. The reason I have to pass this delegate is, I am performing some activity (i.e. uploading) in Class2 and after I am uploading each part, I want to inform the Class1 about my progress so that it could be displayed in the progress bar.
Thanks..
Siddhartha Mehta
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This is an edited version of your code which should do the trick. Note that you were already pretty close yourself.
public delegate bool ProgressDelegate(string fileName, long size);
public class Class1
{
public Class1()
{
ProgressDelegate progressDel = new ProgressDelegate(UploadPro
Class2 class2 = new Class2(arg1, arg2, progressDel);
...
}
public static bool ProgressDelegate(string, long)
{
...
...
}
}
public class Class2
{
ProgressDelegate progressDel;
public Class2(arg1, arg2, ProgressDelegate progressDel)
{
this.progressDel = progressDel;
...
...
}
public void SomethingThatUsesDelegate(
{
bool result = progressDel("filename", 123456);
}
}
I tried with what you said but the thing is I have Class1 and Class2 in 2 different packages. Also the package for Class1 is using the dll from Class2. I get an error message when I try to build package for Class2 that the ProgressDel namespace could not be found.
Do I need to again declare a delegate again in Class2 like below.
public delegate bool ProgressDelegate(string, long)
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by: bgungorPosted on 2003-02-19 at 12:46:28ID: 7983529
Define the delegate and an event of your delegate type in Class2.
In Class1, before you use Class2, subscribe to the event and provide a message handler.
In class 2: (setting up handler definition (delegate) and event)
public delegate MyMessageHandler(object sender, string message);
public event MyMessageHandler MyMessage();
In Class 1:
private MyHandler(object sender, string message){
// Handler function
MessageBox.Show(message);
}
private UsingClass2()
{
Class2 myClass2 = new Class2();
myClass2 += new Class2.MyMessageHandler(My
}
Then to notify class1 from Class2:
In Class 2:
public void DoingSomething()
{
MyMessage(this,"Hey, something happened");
}
Hope this helps,
Bg