title: Custom column in LinqServerModeDataSource
body: <p>I have table in my database names User with fields:</p>
  
  <pre><code>Id
  FirstName
  LastName
  LoginName
  </code></pre>
  
  <p>Now I would like to present this table in <code>ASPxGridView</code> using <code>LinqServerModeDataSource</code>.</p>
  
  <p>What I did is :</p>
  
  <pre><code>&lt;dxdtlnq:LinqServerModeDataSource ID="LinqServerModeDataSource1" runat="server"          OnSelecting="LinqServerModeDataSource1_OnSelecting"
    ContextTypeName="MyContext" EnableDelete="True" 
    EnableInsert="True" EnableUpdate="True" TableName="Users" &gt;
  &lt;/dxdtlnq:LinqServerModeDataSource&gt;
  
  protected void LinqServerModeDataSource1_OnSelecting(object sender, LinqServerModeDataSourceSelectEventArgs e) 
  {           
     MyContext context = new MyContext();
  
     var qry = from s in context.Users select s;
     e.QueryableSource = qry;
  }
  </code></pre>
  
  <p>That works great with my ASPxGridView. I can display data, insert and delete but now I would like to have additional column <code>UserName</code> which is <code>FirstName</code> + <code>LastName</code>.</p>
  
  <p>So I did something like that:</p>
  
  <p>Added appropriate column to my ASPxGridView (FieldName = "UserName")
  and modified OnSelecting handler:</p>
  
  <pre><code>protected void LinqServerModeDataSource1_OnSelecting(object sender, LinqServerModeDataSourceSelectEventArgs e) {
              KozuModelDataContext context = new MyContext();
  
          var qry = (from s in context.Substitutions
                     select new
                                {
                                    Id = s.Id,
                                    FirstName = s.FirstName,
                                    LastName = s.LastName,
                                    LoginName = s.LoginName,
                                    UserName = s.FirstName + " " + s.LastName,
                                }).AsQueryable();
  
          e.KeyExpression = "Id";
          e.QueryableSource = qry;
      }
  </code></pre>
  
  <p>Now data in the grid is displayed buyt when I want to insert or edit data fields cannot be filled, textboxes doesnt respond in inserting form I cant type in any text.</p>
  
  <p>Is there any solution for inserting and editing data in this manner ?</p>
  
  <p>Thanks for help</p>