title: populate combobox with datatable select query
body: <p>I have a datatable which contains a list of clients, this is then assigned to the datasource of a combobox.</p>
  
  <p>I then have another datatable that contains a list of clients sites, when the combobox is changed it should perform a select on the sites datatable and return only rows that match and fill the sites combobox.</p>
  
  <p>Issue is it returns System.Data.DataRow instead of the data contained in the sitename column!</p>
  
  <pre><code>public frmTechSupportCall()
  {
      cboxClientName.DataSource = parentfrm._ClientsList;
      cboxClientName.DisplayMember = "companyname";
      cboxClientName.ValueMember = "client_id";
      cboxClientName.SelectedIndex = 1;
      cboxClientName.Refresh();
  }
  private void cboxClientName_SelectedIndexChanged(object sender, EventArgs e)
  {
      //var temp = cboxClientName.SelectedValue;            
  
      if (cboxClientName.SelectedValue.GetType().ToString() == "System.Int32")
      {
          //DataRow[] dr = parentfrm._ClientsSites.Select(@"client_id = " + cboxClientName.SelectedValue);                
          cboxClientSite.DisplayMember = "sitename";
          cboxClientSite.ValueMember = "site_id";
          cboxClientSite.DataSource = parentfrm._ClientsSites.Select(@"client_id = " + cboxClientName.SelectedValue);
          //cboxClientSite.BindingContext = this.BindingContext;
          //_ClientsList.Rows.InsertAt(drow, 0);
          //cboxClientSite.Items.Add(new object[] { 0, "--Please Select --" });
          //cboxClientSite.SelectedIndex = 0;
      }
  }
  </code></pre>