How is filtering applied to RadGrid?

[Sean Severson]

Hello,

I am working to better understand how filtering is applied to the RadGrid and if I can determine if an item in the grid will be visible or not (due to a filter being applied) in the ItemDataBound event.   Could someone point me to documentation that explains how filters are applied and the various events I could use to either determine what is being filtered or affect what will be filtered?

My specific use for this is to generate a unique list of items in a specific column in the grid after the filter is applied.  I have determined that the ItemDataBound event fires when a filter will be applied, but have been unable to detemine how the filter is applied or if there is an event exposed to me that would allow me to see this.

Thanks,

Sean Severson

[Shinu]

Hello Sean Severson,

I am not sure of your requirements.Please check this to see if this helps.
This code shows how to access the currently filtering column and the filter function being used.

C#:

protected void RadGrid1_ItemCommand(object sender, GridCommandEventArgs e)
{
    if (e.CommandName == RadGrid.FilterCommandName)
    {
        Pair filterPair = (Pair)e.CommandArgument;
        String pair = filterPair.First.ToString(); //Gets the Filter function
        String pair1 = filterPair.Second.ToString(); //Gets the Filter Column
    }

}

Thanks,
Shinu

[Sean Severson]

Shinu,

Thank you for the code.  However, I am looking for an explenation of when and how the filter is applied.  For example, does the RadGrid spin through all of the records in its datasource and check the records against the filter properties to determine if the record should be displayed and, if not, skip over it?  In what event does this occur?  Can I tap into that event in order to perform some processing for each row that should/should not be displayed?

Thanks.

Sean Severson

[Eyup]

Hi Sean,

When the users initiates a filter command, RadGrid builds the FilterExpression for each column and makes a query to the datasource and displays only the returned items. Therefore, the grid rebinds internally every time when filtering is applied, which fires the ItemDataBound event.

I have attached a sample RadGrid web site demonstrating how you can determine whether a column has been filtered. Please check out the attached application and let me know if it helps you.

Regards,
Eyup
Telerik