Filter detail tables from MasterTableView

[Dylan]

Let's say I have a grid containing a set of Schools, and each of the schools has a detail table containing a list of courses. I'm looking for a way to filter the schools and courses by course title through the use of a FilterExpression. As of now, I am iterating through each school item and and setting the FilterExpression of the NestedTableView. Not only is this method cumbersome, but it only filters the courses, not the schools, so any schools without courses after filtering display "No child records to display." 

[Dylan]

To clarify, I do not want the rows (schools) that have empty detail tables (no courses) to be displayed.

[Princy]

Hi Dylan,

I guess you want to set the Initial Filter for Detailtable. You can set the FilterExpression inside the OnDetailTableDataBind event as follows:

C#:

protected void RadGrid1_DetailTableDataBind(object source, Telerik.Web.UI.GridDetailTableDataBindEventArgs e)
{
   GridDataItem dataItem = (GridDataItem)e.DetailTableView.ParentItem;
   switch (e.DetailTableView.Name)
    {
    case "Courses":
        {
          e.DetailTableView.FilterExpression = "(CoursesColumn = SomeValue)";
          GridColumn column1 = e.DetailTableView.GetColumnSafe("CoursesColumn");
          column1.CurrentFilterFunction = GridKnownFunction.Contains;
          break;
        }
    }
}

Below code snippet shows how to hide the Detailtable with no records, you may hide its expand/collapse image also.

C#:

protected void RadGrid1_ItemCreated(object sender, GridItemEventArgs e)
{
    if (e.Item is GridNoRecordsItem) e.Item.OwnerTableView.Visible = false; //Hide Detailtable with no Records
}
protected void RadGrid1_PreRender(object sender, EventArgs e)
{
   HideExpandColumnRecursive(RadGrid1.MasterTableView); //Hide Expand/Collapse image
}
public void HideExpandColumnRecursive(GridTableView tableView)
{
    GridItem[] nestedViewItems = tableView.GetItems(GridItemType.NestedView);
    foreach (GridNestedViewItem nestedViewItem in nestedViewItems)
    {
        foreach (GridTableView nestedView in nestedViewItem.NestedTableViews)
        {
            if (nestedView.Items.Count == 0)
            {
                TableCell cell = nestedView.ParentItem["ExpandColumn"];
                cell.Controls[0].Visible = false;
                cell.Text = " ";
               // nestedView.ParentItem.Visible = false; //To hide the parent row
            }
            if (nestedView.HasDetailTables)
            {
                HideExpandColumnRecursive(nestedView);
            }
        }
    }
}

Thanks,
Princy

[Dylan]

Thanks for the reply Princy. Unfortunately, this is not exactly what I was looking for. The solution you provided only hides the detail tables, but it doesn't filter their parent items out of the school table. I'm looking for a way to filter the schools by course title. In SQL, it would look like this:

select * from Schools
join Courses on Courses.SchoolId = Schools.SchoolId
where Courses.CourseTitle like '%filter_value%'

Hopefully this is a little more clear.

Thanks,
-Dylan

[Angel Petrov]

Hi Dylan,

I have to say that the desired functionality can not be achieved since the CourseTitle field is not included in the Scools table definition. However you can achieve the desired effect by first filtering the result and then binding it to the grid. For example if the grid uses advanced data-biding(like demonstrated here) you can use the SQL select command from your last post to populate the RadGrid. As a result of this only the schools with the desired course will be available.

Regards,
Angel Petrov
Telerik