title: Operator '>=' incompatible with operand types 'String' and 'Object'
body: <p>I want to create search using linq, I have User table in SQL with two <code>nvarchar</code>columns FName and LName and a PK of Id and other columns.</p>
  
  <p><strong>aspx</strong>:</p>
  
  <pre><code> &lt;asp:TextBox ID="search" runat="server" AutoPostBack="True" 
                              ontextchanged="search_TextChanged"&gt;&lt;/asp:TextBox&gt;    &lt;br /&gt;      
    &lt;asp:ListBox ID="found" runat="server" Height="400px" Width="300px" 
                                 AutoPostBack="True" DataSourceID="LinqUserSearch" DataTextField="Users" 
                                 DataValueField="Id"&gt;
    &lt;/asp:ListBox&gt;   
    &lt;asp:LinqDataSource ID="LinqUserSearch" runat="server" 
                                 ContextTypeName="Zhotel.User" EntityTypeName="" GroupBy="Id" 
                                 OrderBy="FName, LName" OrderGroupsBy="key" 
                                 Select="new (key as Id, it as Users)" TableName="Users" 
                                 Where="FName &amp;gt;= @FName &amp;amp;&amp;amp; LName &amp;gt;= @LName"&gt;
          &lt;WhereParameters&gt;
           &lt;asp:ControlParameter ControlID="search" Name="FName" PropertyName="Text" 
                                         Type="String" /&gt;
         &lt;asp:ControlParameter ControlID="search" Name="LName" PropertyName="Text" 
                                         Type="String" /&gt;
    &lt;/WhereParameters&gt;
    &lt;/asp:LinqDataSource&gt;
  </code></pre>
  
  <p>but in runtime the above code gives me this error.</p>
  
  <pre><code>     Operator '&gt;=' incompatible with operand types 'String' and 'Object'
  </code></pre>
  
  <p>I use EF and ASP.NET 4.</p>