How to use ASP.NET <%= tags in server control attributes?

Question

This works:

<span value="<%= this.Text %>" />

This doesn't work:

<asp:Label Text="<%= this.Text %>" runat="server" />

Why is that?

How can I make the second case work properly, i.e., set the label's text to the value of the "Text" variable?

Answer 1

Use Data binding expressions

<asp:Label ID="Label1" runat="server" Text="<%# DateTime.Now %>" ></asp:Label>

Code behind,

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