Posts Tagged ‘gridview’

String Checkbox Control

December 9, 2008

I want to display an array of checkboxes in a gridview.
It should look like this:

But, there is a trick – my database query returns booleans, but the only thing I can bind to the “checked” property of the asp:checkbox control is a string. Too bad. I’ll include some of the work arounds I attempted – I thought they were interesting, but nothing worked.

(OOPS - word press is deleting my code ... sorry)

            <asp:Label ID="lblTest" runat="server" Text='' />

<asp:CheckBox ID="test" runat="server" Checked='' />
<asp:CheckBox ID="test" runat="server" Checked= />

The checkbox above returned “InvalidCastException”. Take my word for it, I tried many variations on the above.

So how did I eventually get the display to work?
I think there are two possible ways.
I did not attempt a server side handling of the row-data-bound event to find the checkbox control and set it to the correct value, although I think that would work.

Instead, I made a simple user control called a StringCheckBox, and set it with the “1” or “0” that my bind syntax was producing, and that worked well.

REVISION – when a simple checkbox is printed, it never prints as checked. I don’t know why. I changed the control so that it displays two images instead of the checkbox.
Here is the (revised) server side of the control in its entirety:

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace TBRSurvey.UTReports
public partial class ctlStringCheckBox : System.Web.UI.UserControl

private string m_checked ="";
public string ctl_checked
get { return m_checked; }
set { m_checked = value; }


protected void Page_Load(object sender, EventArgs e)
CheckBox1.Checked = false;
// images from
imgCheckBox.ImageUrl = "~/images/checkbox.gif";

if (m_checked == "1")
CheckBox1.Checked = true;
imgCheckBox.ImageUrl = "~/images/checkboxchecked.gif";
if (m_checked.ToLower() == "true")
CheckBox1.Checked = true;
imgCheckBox.ImageUrl = "~/images/checkbox.gif";