Question

I’m trying to get a Gridview “select” link to drill down to a specific page for the selected row in ASP.NET with C#. This gridview is generated dynamically in the page_load, and is databound from a fairly simple SQL select query. Each row has a unique id, and I would like this to be passed as a parameter in the url when the select button is clicked for that row. So, when you click the “select” button on the row with an id value of 9 (note – not the id as defined by the gridview, but the one from the SQL query) you are redirected to an address such as moreDetail.aspx?id=9.

However, when trying to pass the id into the event handler I’ve hit issues… GridView.SelectedIndexChanging takes the usual (object sender, EventArgs e) as parameters and nothing else, and since the Gridview is created at Page_Load the EventArgs class is useless. I can’t seem to find any way to pass the id that I have retrieved earlier into the event handler.

After lots of searching,I tried creating a class that extends EventArgs (obviously with my extra parameter added in), but it seems using any parameters other than (object sender, EventArgs e) just won’t work. I could theoretically redo the SQL query within the event handler, but that seems to me a terrible way to achieve what I’m looking for, so I’m hoping someone will be able to see what I’ve got wrong here, because I’m sure I’m missing something obvious.

Some code – grid.SelectedRow.Cells[0] will contain the parameter I want to pass:

In Page_Load:

GridView grid = new GridView();  
grid.DataSource = source;  
CommandField selectField = new CommandField();  
selectField.ShowSelectButton = true;  
selectField.SelectText = "View Jobs";  
grid.Columns.Add(selectField);  
grid.SelectedIndexChanging += grid_SelectedIndexChanging;  
grid.DataBind();  
content.Controls.Add(grid);  

And the Event Handler:

    protected void grid_SelectedIndexChanging(object sender, EventArgs e)
    {
        Response.Redirect("ViewCustomer.aspx?id=" + grid.SelectedRow.Cells[0]);
    }

Obviously this doesn’t work because the scope of grid doesn’t extend to the handler…but how can I get access to that data?

Answer 1

You need to cast sender to GridView to reference your calling GridView:

protected void grid_SelectedIndexChanging(object sender, EventArgs e) 
{ 
    GridView grid = (GridView)sender;
    Response.Redirect("ViewCustomer.aspx?id=" + grid.SelectedRow.Cells[0]); 
}