How can I access an IFRAME from the codebehind file in ASP.NET?

Question

I am trying to set attributes for an IFRAME html control from the code-behind aspx.cs file.

I came across a post that says you can use FindControl to find the non-asp controls using:

The aspx file contains:

<iframe id="contentPanel1" runat="server" />

and then the code-behind file contains:

protected void Page_Load(object sender, EventArgs e)
{
    HtmlControl contentPanel1 = (HtmlControl)this.FindControl("contentPanel1");
    if (contentPanel1 != null)
        contentPanel1.Attributes["src"] = "http://www.stackoverflow.com";

}

Except that it's not finding the control, contentPanel1 is null.

---

Update 1

Looking at the rendered html:

<iframe id="ctl00_ContentPlaceHolder1_contentPanel1"></iframe>

i tried changing the code-behind to:

HtmlControl contentPanel1 = (HtmlControl)this.FindControl("ctl00_ContentPlaceHolder1_contentPanel1");

if (contentPanel1 != null)
    contentPanel1.Attributes["src"] = "http://www.clis.com";

But it didn't help.

i am using a MasterPage.

---

Update 2

Changing the aspx file to:

<iframe id="contentPanel1" name="contentPanel1" runat="server" />

also didn't help

---

Answer

The answer is obvious, and unworthy of even asking the original question. If you have the aspx code:

<iframe id="contentPanel1" runat="server" />

and want to access the iframe from the code-behind file, you just access it:

this.contentPanel1.Attributes["src"] = "http://www.stackoverflow.com";

Answer 1

If the iframe is directly on the page where the code is running, you should be able to reference it directly:

contentPanel1.Attribute = value;

If not (it's in a child control, or the MasterPage), you'll need a good idea of the hierarchy of the page... Or use the brute-force method of writing a recursive version of FindControl().