Exception in ASP.NET WEB Application

Question

I have a function in an application:

private void ds_ItemBound(object sender, DataGridItemEventArgs e)

where in this line:

((System.Web.UI.WebControls.CheckBox)(e.Item.Cells[3].Controls[0])).Checked = false;

I get an exception:

Unable to cast object of type 'System.Web.UI.LiteralControl' to type 'System.Web.UI.WebControls.CheckBox'.

How do I solve this casting error?

Thanks for your help.

pls verify e.Item.Cells[3].Controls[0] control type is label or checkbox, you can check it on quick watch e.Item.Cells[3].Controls[0] while debugging — Jignesh Variya
– Jignesh Variya, Commented Apr 6, 2017 at 6:04
Please provide the DataGrid markup so we can have a better idea of what we are looking at here. — Jon P
– Jon P, Commented Apr 6, 2017 at 6:13
@JigneshVariya e.Item.Cells[3].Controls[0] is System.Web.UI.LiteralControl — Rafael
– Rafael, Commented Apr 6, 2017 at 6:18
@JonP the check box markup looks like <asp:CheckBox ID="lblEditCheck" runat="server" TabIndex="0" Width="30px" CssClass="ColumnHeader" /></td> — Rafael
– Rafael, Commented Apr 6, 2017 at 7:02
But we are still lacking where it sits in the DataView. Please provide that context in the question itself — Jon P
– Jon P, Commented Apr 6, 2017 at 22:55

Reddog · Accepted Answer · 2017-04-06 07:12:51Z

2

It would seem that your first control in the forth column is not a checkbox. I would advise using the FindControl function instead of your args' Item property.

private void ds_ItemBound(object sender, DataGridItemEventArgs e)
{
    if (e.Item.ItemType != ListItemType.Item && e.Item.ItemType != ListItemType.AlternatingItem) return;

    var checkbox = (CheckBox) e.Item.FindControl("lblEditCheck");
    checkbox.Checked = false;
}

edited Apr 6, 2017 at 7:12

answered Apr 6, 2017 at 6:07

Reddog

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3 Comments

Rafael Over a year ago

e.Item.Cells[3].Controls[0] is System.Web.UI.LiteralControl . Thanks for the help.

Reddog Over a year ago

You might find that you're getting an ItemBound even for the header/footer row or something like that. Added a check to my sample accordingly.

Rafael Over a year ago

Hi, thanks for the answer. However I still get the error, now I get that checkbox variable is null. I still don't get how to resolve the error. The problem is that I have multiple rows that should be populated in a table, I get only one row + an exception :(

borkovski · Accepted Answer · 2017-04-06 06:05:45Z

0

Make sure your CheckBox is first in the fourth cell, it looks like there's a Literal. Please post fragment of your page code to confirm.

answered Apr 6, 2017 at 6:05

borkovski

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