Server side remove filter

[Ahmed Ilyas]

How is it possible to remove a filter from server side? For example I need to use combined filtering of columns.
if we have 5 columns and we filter 3 of them initially, this is fine however if the user changes the filter for one of the columns, the filter expression is incorrect (understandbly why because I am concatinating the existing expression along with the new one)

is there a way to remove a specific filter and then apply the new filter?

If (String.IsNullOrEmpty(Me.grdShiftObservation.MasterTableView.FilterExpression)) Then
   Me.grdShiftObservation.MasterTableView.FilterExpression = dtFromString
Else
   Me.grdShiftObservation.MasterTableView.FilterExpression =  Me.grdShiftObservation.MasterTableView.FilterExpression & " AND " & dtFromString
end if

so the initial expression maybe "DateTime >= #...#"
Then if the user selects a different filter then the expression will be:

"DateTime >= #...# AND DateTime <= #...#"

which is not what I want. In this case it would be DateTime <= #...#

so I just want to remove from the FilterExpression the related column filter completely

[Ahmed Ilyas]

From the behavior I am seeing (combination of server side and ajax filtering), I believe I can just forget about doing the filter concatination and just set the filter expression to the filter I want and that seems to work and the client side filters it correctly too with any other filters being applied.

update: actually forget that. I was wrong. not sure whats going on or how it really works. I see in our solution, which I am taking over and working with, that both AJAX and server filtering are taking place. So its hard to get the correct filter expression to be built for a custom server filter.
All I want is to remove a filter that already possibly exists (server side) from the FilterExpression

[Tsvetina]

Hello Ahmed,

When using custom filter expressions, you need to take care of creating, adding and clearing it manually, as RadGrid cannot handle it itself. I am attaching a sample project showing one way to do this. You can see that the last column is filtered by a list of comma-separated values. I keep the custom filter in ViewState, so I can remove it when needed.
I hope this helps.

Regards,
Tsvetina
the Telerik team