How to dynamically change the visibility of html <a> tag in asp.net

I w开发者_运维问答ant to hide an anchor tag based on the value of session object. How am I suppose to do it?

Assuming you wish to do it on server side - the code will be something such as

<a id="MyLink" runat="server" ...

MyLink.Visible = Convert.ToBoolean(Session["MyKey"]);

Note runat="server" in the markup(aspx) file which is important to refer the control in code-behind.

Add ID and runat attributes to the anchor:

<a id="anchor" runat="server"></a>

Set visibility in the code-behind:

protected void Page_Load(object sender, EventArgs e)
{
   anchor.Visible = (bool)Session["showAnchor"];
}

As Alex above, but for neatness I tend to put the visibility code inside the aspx tag if it isn't too long, like:

<a id="aid" runat="server" href="link" Visible='<%# (Session["value"] != null) ? Session["value"] : bool.Parse("false") %>' >Text</a>

Haven't tried with a session yet, but it has worked with codebehind functions and bound values, so I don't see why it shouldn't work with session variable.

On a related note, I haven't managed to pass booleans directly this way, hence the use of bool.Parse(""). Don't understand why it won't work directly, since it works when you use values like Visible='<%# string.IsNullOrEmpty() %>'...

<a id="aid" runat="server" href="link">Text</a>


if (Session["value"] != null)
        {
            aid.Visible = true;
        }
        else
        {
            aid.Visible = false;
        }

It depends if you want to hide the link on a postback / initial load or after the page has already been delivered to the client.

If you want to hide the link on postback / initial load, you can add the runat="server" attribute to the link and set its Visible property in the code behind.

If you want to hide the link on a page that is already on the client, you can poll the server with Ajax calls and then hide the link using javascript.