Delegate to an instance method cannot have null 'this'.

hello again... i have solved tjhe problem by using lambda as follow:

ImageMap1.Click += (sender, args) =>
            {
                _ = new EventHandler(imgMap_Click);                
            };

and the click method is:

 protected void imgMap_Click(object sender, EventArgs e)
        {
            string email = HttpUtility.UrlEncode(Email);
            string title = HttpUtility.UrlEncode(Title1);
            string redirectUrl = "adpage.aspx?email=" + email + "&title=" + title + "&message=" + "Ad registered!";
            Response.Redirect(redirectUrl);
        }

the table with its items are filled in the page. but when i click on the image,it stays in the same page with the table??!! it doesnt go to the adpage.aspx???!!! something in empty or null and i dont know which... i dont know either how i should assign and assign with what... appreciate your respond, kind regards

Amit Mohanty and Tahir Ansari, thanks for your responds... but in your cases i get this error:

No overload for imgMap_Click matches delegate ImageMapEventHandler, therefore i must define it before, but it requires assignment of mgMap_Click, which i dont know assign to what?

thanks if you respond, kind regards

The error you are encountering is because you are trying to assign a null value to the imgMap_Click delegate, which is not allowed when using new ImageMapEventHandler(imgMap_Click).

To fix this issue, you need to assign the imgMap_Click delegate to the actual method you want to handle the ImageMap click event. In your case, the method you want to handle the click event is imgMap_Click.

ImageMap ImageMap1 = new ImageMap();
ImageMap1.Height = 150;
ImageMap1.Width = 150;
ImageMap1.ImageUrl = GridView1.Rows[rowind].Cells[11].Text;

// Define the imgMap_Click method
ImageMapEventHandler imgMap_Click = new ImageMapEventHandler(imgMap_Click);

// Attach the imgMap_Click method to the Click event of ImageMap1
ImageMap1.Click += imgMap_Click;

tcell_2.Controls.Add(ImageMap1);
trow_2.Controls.Add(tcell_2);
mytable.Controls.Add(trow_2);

Make sure to keep the imgMap_Click method unchanged:

protected void imgMap_Click(object sender, ImageMapClickEventArgs e)
{
    // Your code to handle the ImageMap click event goes here
    // ...
}

C#:

ImageMap ImageMap1 = new ImageMap();
ImageMap1.Height = 150;
ImageMap1.Width = 150;
ImageMap1.ImageUrl = GridView1.Rows[rowind].Cells[11].Text;
ImageMap1.Click += imgMap_Click; // Use the existing method directly as the event handler
tcell_2.Controls.Add(ImageMap1);
trow_2.Controls.Add(tcell_2);
mytable.Controls.Add(trow_2);

Make sure imgMap_Click method defined in your code-behind:

protected void imgMap_Click(object sender, ImageMapClickEventArgs e) 
{
    // Your event handling logic here
    // ...
}

directly using the imgMap_Click method as the event handler without creating a new delegate instance, you should be able to resolve the "Delegate to an instance method cannot have null 'this' error.