How do I programmatically set property of control in aspx file?

This may be a very dumb question but I can't seem to get it working. I use at many places the following syntax for dynamically binding a property of a control in aspx file to the resource entry, e.g.

<SomeFunnyControl Text="<%$ Resources : ResClass, ResEntry %>" />

I want to do a similar thing with a class containing some constants, something like

<SomeFunnyControl Text="<%= MyConstantsClass.MyStringConstant %>" />

But this doesn't seem to work, it simply sets the text to the exact expression without evaluating it. I am using ASP.NET 3.5 开发者_如何学运维btw.

I have tried the databinding approach but I get an HttpParseException saying

Databinding expressions are only supported on objects that have a DataBinding event.

This article: The CodeExpressionBuilder might be interesting/helpful (although written for ASP.NET 2.0).

It (seems) to enable you to write ... Text="<%$ Code: DateTime.Now %>" .... That might help, no? It is quite a bit of overhead, though.

Your code should look like this:

<asp:Label ID="lblMyStringConstant" runat="server" Text='<%# MyConstantsClass.MyStringConstant %&>'></asp:Label>

You also need to call DataBinding on that control, like this:

lblMyStringConstant.DataBind();

(It is not necessary if you are calling DataBind on entire Page or parent container of this label, because it will call DataBind for all its children)

<asp:Label ID="lbl" Text="<%# SomeText %>" runat="server" />

Then call lbl.DataBind(); or databind some container of the label.

If you have it like this it should work actually:

public static class MyConstantsClass
{
   public static string MyStringConstant = "Hello World!";
}

or alternatively

public class MyConstantsClass
{
   public const string MyStringConstant = "Hello World!";
}

If you declare it like

<asp:Label ID="Label1" runat="server" Text="<%= MyNamespace.MyConstantsClass.MyStringConstant %>"></asp:Label>

it won't work and the output will be "<%= MyNamespace.MyConstantsClass.MyStringConstant %>".

What you could do alternatively is to write it like this:

<asp:Label ID="lblTest" runat="server"><%= MyNamespace.MyConstantsClass.MyStringConstant %></asp:Label>

This works perfectly for me, but note you have to provide the fully qualified namespace to your class in the ASPX definition. At least otherwise it didn't work for me.