How to access span class in codebehind?

Question

Is it possible display/hide spans in the codebehind based on their class? I've been able to do this with a span's id but not with classes.

markup:

<span runat='server' id='myId' class='myClass'>some text</span>

codebehind:

protected override void OnPreRender(EventArgs e)
{
    // This works
    myId.Visible = false;

    // This doesn't work
    myClass.Visible = false;
}

I get the error "The name myClass does not exist in current context". But the codebehind has no trouble with the id.

Answer 1

No, there is nothing that exists that lets you refer to something by class; only the ID actually works in the code-behind. You can find the object by ID, and then check it's class, or you can define a container control around something:

<asp:Panel ID="X" runat="server">
.
.
</asp:Panel>

And using this, you can loop through the controls in the panel, check the class, and process it, like:

foreach (var c in X.Controls)
{
   if (c is WebControl && ((WebControl)c).CssClass == "myClass")
      //Do something
   else if (c is HtmlControl && ((HtmlControl)c).Attributes.ContainsKey("class") && ((HtmlControl)c).Attributes["class"] == "myClass")
      //Do something

}

That's possible to do. You could also do it at the page level, but would have to do it recursively, and it may affect your apps performance.

Answer 2

You could try something like this:

<span runat='server' id='myId' class='myClass'>some text</span>
    ...
</span>


myId.Attributes.Add("style", "display:none;");

Answer 3

Of course it will not. You are using class name as an Id.

You can select the control using Contols Collection on Page object.

foreach (Control c in Page.Controls)
    {
            if (c.CssClass == "myClass")
            {
                c.Visible=false;
            }
    }