[Solved] Grid Custom Template Force Post Back

[The KID]

I'm using a grid and i would like to have a button that when the user clicks on it binds my CheckBoxList that i have later on the page. I placed an image button in a template field but i'm guessing i need to force a postback so on the page reload the CheckBoxList can get bound to the selected item in the grid.

Does anyone know how to do this? I was thinking that maybe i need to go in the code behind and on the grid item create event register my image button with the ajax manager?

I don't have any emotional ties to the template field and the image button so if there is a better way to bind the selected grid item to my CheckBoxList , I'm open to suggestions.

--Mike

[Veli]

Hello Mike,

GridTemplateColumn with an ImageButton would work for you, but you can also use a GridButtonColumn that saves you some markup and does the job. You will need to set a custom command name for your button, and in the ItemCommand event handler of RadGrid, implement your custom code under this command name. Something like the following:

void RadGrid1_ItemCommand(object source, GridCommandEventArgs e)
    {
        if (e.CommandName == "MyCustomCommand")
        {
            //..your custom code
        }
    }

If you need to specify certain command arguments for each data item from RadGrid, you can do this in the ItemDataBound event handler in the following way:

    void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
    {
        if (e.Item is GridDataItem)
        {
            GridDataItem item = (GridDataItem)e.Item;
            (item["ButtonColumn"].Controls[0] as Button).CommandArgument = item.ItemIndex;
        }
    }

This piece of code sets the ItemIndex value of the current item as the CommandArgument of the respective button control in the GridButtonColumn.

As for updating controls outside of Ajaxified RadGrid, you will need to register all of these controls with the Ajax manager, so that updating these controls from inside RadGrid can be accomplished using Ajax callbacks.

Best regards,
Veli
the Telerik team

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[The KID]

Thank you for the excellent example. I think I almost got it working up to the part of registering the control with the script manger. This is what I used to try to register the control but it throws an error because the button is null?

protected void RadGrid1_ItemCreated(object sender, GridItemEventArgs e)
{
     if (e.Item is GridDataItem)
     {
          //Get the properties of the button
          ImageButton btn = (ImageButton)e.Item.FindControl("MyButton");

          //Get the current script manager from the page
          ScriptManager SM = ScriptManager.GetCurrent(Page);

          //Register the control with the scriptmanager to preform the post back
          SM.RegisterPostBackControl(btn);
     }
}

Here is how i declare the button that i'm working with:

<telerik:GridButtonColumn
     UniqueName="MyButton"
     HeaderText="My Button"
     ButtonType="ImageButton"
     ImageUrl="~/Images/Icons/house_go.gif"
     CommandName="StoredProcedureId"
     CommandArgument="StoredProcedureId">
<telerik:GridButtonColumn>;

So I'm attempting to bind the ID to button so i can use it on the item command like you instructed i could do previously

protected void RadGrid1_ItemCommand(object source, Telerik.Web.UI.GridCommandEventArgs e)
{
     if (e.CommandName == "StoredProcedureId")
     {
          //My logic here ..
     }
}

Any ideas as to why my button is null? Would it be because in the code i told it to look for an ImageButton and the grid uses it's own special image button?
 

[Veli]

Hello Mike,

You need to access the button through the Controls[] collection of the current item cell:

void RadGrid1_ItemCreated(object sender, GridItemEventArgs e)
{
    if (e.Item is GridDataItem)
    {
        GridDataItem item = (GridDataItem)e.Item;
        ImageButton imgButton = (ImageButton)item["MyButton"].Controls[0];
    }
}

This should work now and you can handle your custom command in the ItemCommand event handler. Please note that for a GridButtonColumn of ButtonType="ImageButton", you need to set a valid ImageUrl for the custom command to work, otherwise the ItemCommand event is not fired.

Sincerely yours,
Veli
the Telerik team

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