Delegate and EventArgs Question

Hi,

I am very new to programming and i have a quick question. I am developing a webpage and I want a delegate to handle a button click. I am programming in J#. What I want to do is display the element found at ArrayList(i) after clicking on a button.

Example:

<input type="button" id="display" value="Display" runat="server" onserverclick="write(<%=i %>)" />

I want the method 'write' to take the value 'i'.

The method will be:

ArrayList theList;

public void write(int i)
{
aDiv.set_InnerHtml("Value in array at index " + i + "is" + theList.get_Item(i));
}

I get the error: The argument in the creation of delegate 'System.EventHandler' must name a method.

I am so confused. This sounds like an easy question, but I'm not sure how to write it.
Please help, thank you.

Allan

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Delegate and EventArgs Question

Thiruvenkadam
Thank you very much for the response Thilak. I inserted the snippet in my code but it did not display anything. I studied your code and I am starting to realize what is happening. I am just confused on how the selected "i" will be printed out. Also, where you inserted "i++", is that correct I will continue to study your code. Again, I really appreciate you responding Thilak.
Chuck D
Hi Alan,

I have given the code snippet for example only. In your first question you used i in your script. can you clarify me what is i in your code.i++ need not be in that place it can be any where.but make sure that the change i++ occured before binding the event.

regards,

Raj Thilak
IvoGrootjes
Hi,

For passing arguments to eventArgs we have to create a wrapper you can follow the following code snippet for passing argument.

class MyEvent

{

private MyDelegate YouDoIt;

private int param;

public MyEvent(MyDelegate d, int p)

{

YouDoIt = d;

param = p;

}

public void DoIt(Object sender, System.EventArgs e)

{

write(sender, new MyEventArgs(param));

}

}

public class MyEventArgs extends EventArgs

{

public MyEventArgs(int i)

{

myVar = i;

}

private int myVar;

/** @property */

public int get_MyProperty()

{

return myVar;

}

/** @property */

public void set_MyProperty(int value)

{

myVar = value;

}

}

private static int i;

delegate void MyDelegate(Object sender, MyEventArgs e);

MyEvent mevent;

ArrayList theList;

public void write(Object sender, MyEventArgs eventArgs)

{

aDiv.set_InnerHtml("Value in array at index " + eventArgs.get_MyProperty() + " is " + theList.get_Item(eventArgs.get_MyProperty()));

}

protected void Page_Load(Object sender, EventArgs e)

{

theList = new ArrayList();

theList.Add("ra:");

theList.Add("raB");

theList.Add("THR");

i++;

mevent = new MyEvent(new MyDelegate(this.write), i);

display.add_ServerClick(new System.EventHandler(mevent.DoIt));

}

remove onserverclick="write(<%=i %>)" in

<input type="button" id="display" value="Display" runat="server" onserverclick="write(<%=i %>)" />

hope this will work for you.

regards,

Thilak
Dick Grier
I have also tried writing the method:

public void write(Object sender, EventArgs e) {}

I am not sure how to get the arguments in e.
Delegate and EventArgs Question

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