Passing a delegate to a function

[Dom]

Let's say I do this:

MyObject o = new MyObject (this, DoWork);

.... where DoThis is a function in the calling class. How do I pick
this up in the constructor, MyObject?

public MyObject (Form OriginatingForm, <???> ptrDoWork)
OriginatingForm.Invoke (ptrDoWork)


How do I replace <???>.

Dom

 

[Nicholas Paldino [.NET/C# MVP]]

Dom,

Well, you have to have a delegate defined. It looks like it has no
parameters, and no return value, so you can define a delegate like so:

public void DoSomething();

Then, your constructor would be defined as:

public MyObject(Form originatingForm, DoSomething doSomething)
{
OriginatingForm.Invoke(doSomething);
}

Although if you know the object is going to be constructed on the UI
thread, then you can just do:

public MyObject(Form originatingForm, DoSomething doSomething)
{
doSomething();
}

 

[sloan]

HEre is a good article.

http://msdn.microsoft.com/msdnmag/issues/04/05/C20/


Nicholas,

Wouldn't it be

delegate void DoSomething();
?

Dom,

Well, you have to have a delegate defined. It looks like it has no
parameters, and no return value, so you can define a delegate like so:

public void DoSomething();

Then, your constructor would be defined as:

public MyObject(Form originatingForm, DoSomething doSomething)
{
OriginatingForm.Invoke(doSomething);
}

Although if you know the object is going to be constructed on the UI
thread, then you can just do:

public MyObject(Form originatingForm, DoSomething doSomething)
{
doSomething();
}


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

Let's say I do this:

MyObject o = new MyObject (this, DoWork);

... where DoThis is a function in the calling class. How do I pick
this up in the constructor, MyObject?

public MyObject (Form OriginatingForm, <???> ptrDoWork)
OriginatingForm.Invoke (ptrDoWork)


How do I replace <???>.

Dom

 

[Nicholas Paldino [.NET/C# MVP]]

Yes, forgot the delegate keyword. Thanks for the catch.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

HEre is a good article.

http://msdn.microsoft.com/msdnmag/issues/04/05/C20/


Nicholas,

Wouldn't it be

delegate void DoSomething();
?





in
message news:[email protected]...

Dom,

Well, you have to have a delegate defined. It looks like it has no
parameters, and no return value, so you can define a delegate like so:

public void DoSomething();

Then, your constructor would be defined as:

public MyObject(Form originatingForm, DoSomething doSomething)
{
OriginatingForm.Invoke(doSomething);
}

Although if you know the object is going to be constructed on the UI
thread, then you can just do:

public MyObject(Form originatingForm, DoSomething doSomething)
{
doSomething();
}


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

Let's say I do this:

MyObject o = new MyObject (this, DoWork);

... where DoThis is a function in the calling class. How do I pick
this up in the constructor, MyObject?

public MyObject (Form OriginatingForm, <???> ptrDoWork)
OriginatingForm.Invoke (ptrDoWork)


How do I replace <???>.

Dom

 

[Jon Skeet [C# MVP]]

Well, you have to have a delegate defined. It looks like it has no
parameters, and no return value, so you can define a delegate like so:

public void DoSomething();

Correction to typo - to declare the delegate type, you need:

public delegate void DoSomething();

 

[james]

MyObject o = new MyObject (this, DoWork);

... where DoThis is a function in the calling class. How do I pick
this up in the constructor, MyObject?

OriginatingForm is redundant because the DoWork stored a reference to
OriginatingForm when it was created. Delegate's have to reference a
class instance when pointing to an instance method. Then you can
call:

((Form)DoWork.Target).Invoke(DoWork);