Persisting filtering of RadGrid when dynamically create columns

[Ewald]

I build my (ajaxified) grid up dynamically in code. I do that in the Page_Init event so virtual paging is correctly implemented. On every column I have added the AutoPostBackOnFilter = True. When you do this and the user types in the filter in a second column, the filter that was set in the first column is lost.

I guess this is because the grid is recreated and the CurrentFilterFunction and CurrentFilterValue are not persisted because I create the columns dynamically. What is the best solution to solve this?

[Martin]

Hello Ewald,

I have tried to reproduce the issue locally, but without success. Attached is a small sample that works as expected. Please review it and let me know whether I miss something.

In addition I would suggest that you check this online example that demonstrates RadGrid programmatic creation on Page_Init event.

I hope this helps.

All the best,
Martin
the Telerik team

[Ewald]

I have created a simple repro. 

Steps
1. Enter a filter value in the first column
2. Enter a filter value in the second column

Actual result
The first filter value is removed, there is only a filter on the second column

Expected result
Both filter values are applied

<%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %>
<%@ Page Title="Home Page" Language="vb" MasterPageFile="~/Site.Master" AutoEventWireup="false"
    CodeBehind="Default.aspx.vb" Inherits="TweedeFilter._Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
   <telerik:RadScriptManager ID="RadScriptManager" runat="server" AsyncPostBackTimeout="0" />
   <asp:PlaceHolder ID="ph" runat="server" />
</asp:Content>

Imports Telerik.Web.UI

Public Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
        ph.Controls.Add(BuildGrid())
    End Sub

    Private Function BuildGrid() As RadGrid
        Dim col1 = "col1"
        Dim col2 = "col2"

        Dim ret = New RadGrid() With {
                .EnableViewState = True,
                .ID = "myId",
                .AutoGenerateColumns = False
                }

        ret.MasterTableView.EnableColumnsViewState = False

        ret.AllowFilteringByColumn = True
        ret.EnableLinqExpressions = False

        AddHandler ret.NeedDataSource, Sub(sender As Object, e As GridNeedDataSourceEventArgs)
                                           Loaddata(ret)
                                       End Sub

        ret.Columns.Add(New GridBoundColumn() With {.DataField = col1, .AutoPostBackOnFilter = True})
        ret.Columns.Add(New GridBoundColumn() With {.DataField = col2, .AutoPostBackOnFilter = True})

        Return ret
    End Function

    Private Sub Loaddata(ret As RadGrid)
        Dim col1 = "col1"
        Dim col2 = "col2"

        Dim dt As New DataTable

        dt.Columns.Add(col1, GetType(String))
        dt.Columns.Add(col2, GetType(String))

        dt.LoadDataRow(New Object() {"bb", "cc"}, True)
        dt.LoadDataRow(New Object() {"bb", "ff"}, True)
        dt.LoadDataRow(New Object() {"cc", "ff"}, True)
        dt.LoadDataRow(New Object() {"cc", "cc"}, True)
        dt.LoadDataRow(New Object() {"dd", "cc"}, True)
        dt.LoadDataRow(New Object() {"dd", "ff"}, True)
        dt.LoadDataRow(New Object() {"ee", "ff"}, True)
        dt.LoadDataRow(New Object() {"ee", "cc"}, True)

        ret.DataSource = dt
    End Sub
End Class

[Martin]

Hello Ewald,

Reviewing your code I noticed that you have disabled the viewstate of the columns in your grid:

Private Function BuildGrid() As RadGrid
    ...
    ret.MasterTableView.EnableColumnsViewState = False
    ...
End Function

Please turn the columns viewstate on and let me know whether the problem persists.

Kind regards,
Martin
the Telerik team

[Ewald]

Thanks. That did the trick.
I needed it at one point due to http://www.telerik.com/help/aspnet-ajax/grid-changing-structure-dynamically.html. But it seems that I don't need it anymore.

[Rohan]

i am new in TELERIK Control , How to add filter to dynamically created RADGRID 's Template field .

[Princy]

Hello,

The FilterTemplates for the TemplateColumns can be created and assigned dynamically, in the same way as the ItemTemplates and EditTemplates as explained in the following help documentation.
Programmatic Creation.

Thanks,
Princy.