Bind RadComboBox to RadGrid

[RB]

I am following this example to apply the filtering capability in my RadGrid: http://www.telerik.com/forums/replacing-filtertemplate-on-autogenerated-column#epZqFpXIkk6TVsIFktTiug
Currently my combo.DataSource calls the stored procedure but this is very slow. Is there a way I can populate the RadComboBox from the RadGrid instead of calling the same stored proc again?
This is my RadComboBoxControl_DataBinding

 

public void RadComboBoxControl_DataBinding(object sender, EventArgs e)
  {
      RadComboBox combo = (RadComboBox)sender;
      GridFilteringItem container = (GridFilteringItem)combo.NamingContainer;

      combo.DataTextField = colname;
      combo.DataValueField = colname;
      combo.EnableAutomaticLoadOnDemand = true;
      combo.AllowCustomText = true;
      combo.AppendDataBoundItems = true;
      combo.DataSource = new StoredProc().ExecuteTypedDataTable().SelectDistinct(colname);
      combo.DataBind();
      combo.Items.Insert(0, new Telerik.Web.UI.RadComboBoxItem { Text = "All", Value = "All" });
      combo.SelectedValue = selectedValue;
  }

[Eyup]

Hi Ruchi,

You can use a global variable to hold the inquired data:

private static DataTable source = null;
protected void Grid_NeedDataSource(object sender, GridNeedDataSourceEventArgs e)
{
    source = GetGridSource();
    (sender as RadGrid).DataSource = source;
}
public class MyCustomTemplate : ITemplate
{
    protected RadComboBox combo;
    public void InstantiateIn(Control container)
    {
        combo = new RadComboBox();
        ...
        combo.DataBinding += combo_DataBinding;
        container.Controls.Add(combo);
    }
    protected void combo_DataBinding(object sender, EventArgs e)
    {
        combo.DataSource = source;
    }
}

In addition, please note that you should avoid calling DataBind() inside databinding related events.

Hope this helps. Please give it a try and let me know if it works for you.

Regards,
Eyup
Telerik

[RB]

It works. But I forgot to mention that I need only distinct values. The columns which have the filtering capability will have distinct values but the RadGrid does not have distinct values. Hence, is there a way only distinct values will be populated into the RadComboBox? Is there a way to select only distinct values from each column of the RadGrid? 

[RB]

Ignore it. I found the solution.

[RB]

I am trying to implement the "No Filter" option in the dropdown. If "All" is selected, there should be no filtering and all records should be displayed.  But  it does not work. It returns incorrect data.

void RadComboBoxControl_SelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e)
    {
        RadComboBox combo = sender as RadComboBox;
        string filterExpression;

         filterExpression = "([" + colname + "] ='" + e.Value + "')";

        if (e.Value.Equals("All"))
        {
            foreach (GridColumn column in radgrid.MasterTableView.OwnerGrid.Columns)
            {
                column.CurrentFilterFunction = GridKnownFunction.NoFilter;
                column.CurrentFilterValue = string.Empty;
            }
            radgrid.MasterTableView.FilterExpression = string.Empty;

        }
        else
         radgrid.MasterTableView.FilterExpression = filterExpression;
        selectedValue = e.Value;
        radgrid.MasterTableView.Rebind();
    }
}

[Eyup]

Hi Ruchi,

Manipulating the FilterExpression to apply a column filter command can be tricky and complex. I highly suggest that you use the approach demonstrated in this topic to filter with a RadComboBox:
http://demos.telerik.com/aspnet-ajax/grid/examples/functionality/filtering/filter-templates/defaultcs.aspx

If you have difficulties implementing it programmatically, please let me know and I'll gladly help.

Regards,
Eyup
Telerik