Regardign implementing Custom ExpressionBuilder
<p>I want to pass the "DisplayName" column value returned from SqlDataSource's Select command to a custom function and then the return value to be assigned to "DataTextField" property of DropDownList. </p>

<p>I know, I can do this using "CustomExpressionBuilder", I have tried but if I use following:</p>

<pre><code>DataTextField="&lt;%$ MyCustomExpressionBuilder:DisplayName %&gt;" 
</code></pre>

<p>I do not receive the value of the DisplayName field in the overriden "GetCodeExpression" method, but the literal value "DisplayName". </p>

<p>How can I do this? Please help me.</p>

<pre><code>&lt;asp:DropDownList ID="drpCourseType" runat="server" DataSourceID="sqldsCourses" 
                                                 DataTextField="DisplayName" DataValueField="Type" CssClass="FilterDropdown"&gt;
                                                &lt;/asp:DropDownList&gt;
                                                &lt;asp:SqlDataSource runat="server" ID="sqldsCourses"
                                                SelectCommand="SELECT Type,DisplayName FROM CourseTypes ORDER BY OrderID"
                                                 ConnectionString="&lt;%$ ConnectionStrings:connectionString %&gt;"&gt;&lt;/asp:SqlDataSource&gt;
</code></pre>
