CODEWITHSUNDEEP
c#delegatesargument-passing
negu
negu

Reputation: 13

void as an argument

I'm programming in c#. I need a function which creates a Button, specifies its name and some of its events. I need to pass its name and events as arguments. I have done this:

    private void createButton(string name, EventHandler hover, EventHandler click)
    {
        Button button = new Button();
        button.Name = name;
        button.Image = Properties.Resources.print_trans;
        button.MouseHover += new System.EventHandler(hover);
        button.Click += new System.EventHandler(click);
        button.Visible = false;
        this.Controls.Add(button);
    }

In another part of the code I make these calls:

    createButton("cmdPrint", this.Hover, this.Print);
    createButton("cmdMark", this.Hover, this.Mark);

The calls generate this error: "The best overloaded method match for createButton(string, System.EventHandler, System.EventHandler)' has some invalid arguments".

What type of arguments should hover and click be?

Edit:

Jon: Hover and Print are Events:

    private void Hover(object sender, EventArgs e)
    {
        Proofs.ShowInformation((Control)sender);
    }

    private void Print(object sender, EventArgs e)
    {
        Proofs.Print((Control).sender);
    }

The two call lines generate the same error.

Steve: My Events Print and Hover have the typical Event syntax, but I don't know what type should have hover and click in createButton function.

Edit2:

My problem is solved. I just add this delegate:

private delegate void Del(object sender, EventArgs e);

Change the calls:

Del print = this.Imprimir;
Del hover = this.Hover;        
createButton("cmdPrint", this.Hover, this.Print);
createButton("cmdMark", this.Hover, this.Mark);

And change the arguments (in createButton):

private void createButton(string name, Del hover, Del click)

Thanks a lot.

Upvotes: 0

Views: 192

Answers (1)

Steve Wellens
Steve Wellens

Reputation: 20620

The two EventHandler parameters should be functions that have this signature:

void MyFunction(Object sender, EventArgs e)

If you look up EventHandler on the MSDN website, you can see the syntax of this delegate described as:

[SerializableAttribute]
[ComVisibleAttribute(true)]
public delegate void EventHandler(
    Object sender,
    EventArgs e
)

This tells you the return type and the type of the parameters for that signature.

Upvotes: 1

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