Finally I found a good solution for this case.
Here is very good post of Dave Reed:
http://weblogs.asp.net/infinitiesloo...onBuilder.aspx
The short steps to achieve similar result are:
1) Create a class which inherits ExpressionBuilder:
using System;
using System.Collections.Generic;
using System.Text;
using System.CodeDom;
using System.Web.Compilation;
using System.Web.UI;
namespace Helper.Configurators
{
[ExpressionPrefix("InlineCode")]
public class CodeExpressionBuilder : ExpressionBuilder
{
public override CodeExpression GetCodeExpression(BoundPropertyEntry
entry, object parsedData, ExpressionBuilderContext context)
{
return new CodeSnippetExpression(entry.Expression);
}
}
}
2) register the newly created class in Web.Config:
<expressionBuilders>
<add expressionPrefix="InlineCode"
type="Helper.Configurators.CodeExpressionBuilder"/>
</expressionBuilders>
(it must be putted inside <configuration>)
3) and us it:
CategoryImage='<%$ InlineCode: Request.ApplicationPath+ "/App_Themes/"
+Page.Theme+ "/Images/ball_.png" %>'
Enjoy.