Setting a checkbox by using <%# isChecked %> expression

Question

Here is a simplified example of what I am trying to achieve;

<asp:CheckBox runat="server" Checked="<%# this.isChecked %>" id="myCheckBox" />

Then in my code behind;

public partial class _Default : System.Web.UI.Page 
{
    bool _isChecked = true;

    public string isChecked
    {
     get
     {
      return _isChecked.ToString();
     }
    }

    protected void Page_Load(object sender, EventArgs e)
    {
    }
}

I am aware that, in this case, I can simply use myCheckBox.Checked = true, but I'm just using this example for illustration purposes. The real control is a custom one, but I'm not having any luck getting this approach to work. It just seems to ignore the value I'm supplying.

Is it valid to use <%# this.isChecked %> in this manner?

EDIT:

Sorry, I wrote this in a hurry and realise that it's not really clear that I intended "checkbox" to just be an example. I'm just trying to get a server-side bool into any particular attribute of the ASP control, not necessarily the "checked" attribute of the checkbox control.

EDIT 2: Updated my example to use string property rather than boolean field, but it is reporting the following error in my ASPX file now;

Cannot convert type 'string' to 'bool'

Answer 1

If you supply

checked="anything"

it will be checked (in HTML). You need to omit the checked attribute for it to not be checked, so this will not work.

---

After the edit to the question, here is my updated answer:

I would not try to set the attribute in the aspx page, rather I would use the ID and do it in code.

eg.

<asp:Control ID="uxMyControl" runat="server" attributes="other"... />

Code behind:

private Boolean mypropery = false;

Page_Load(object sender, EventArgs e)
{
    this.myproperty = true;
    uxMyControl.attributes = myproperty;
}

Answer 2

No, because you're returning a bool rather than the string (typecasting problem), you need a property rather than a field to work with the databinding expression, and some browsers won't correctly render your checkbox with the words "true/false". Instead, they expect to see checked="checked" to check the box or nothing to un-check it.

Based on your edit, I suspect you have code elsewhere that is trying to set the isChecked boolean. The code fails now that the isChecked name points to a string property instead. Update it to set _isChecked.