How to filter GridTemplateColumns of Telerik's RadGrid

Question

I have two GridTemplateColumns in my RadGrid. The default filtering doesn't work for me and I want to change it.

The GridTemplateColumns are like below:

<telerik:GridTemplateColumn FilterControlAltText="Filter Online column" HeaderText="Online"
    UniqueName="Online">
    <ItemTemplate>
        <asp:CheckBox ID="chkOnline" runat="server" Checked='<%# CheckForOnline(Eval("ID")) %>'
            Enabled="False" />
    </ItemTemplate>
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    <ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="100px" />
</telerik:GridTemplateColumn>

and the other one:

<telerik:GridTemplateColumn FilterControlAltText="Filter FileSize column" HeaderText="FileSize"
    UniqueName="FileSize" Visible="False">
    <ItemTemplate>
        <asp:Label ID="lblFileSize" runat="server" Text='<%# Eval("FileSize") %>'></asp:Label>
    </ItemTemplate>
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    <ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" />
</telerik:GridTemplateColumn>
<telerik:GridTemplateColumn FilterControlAltText="Filter FileSizeChange column" HeaderText="FileSize"
    UniqueName="FileSizeChange">
    <ItemTemplate>
        <asp:Label ID="lblFileSizeChange" runat="server" Text='<%# ChangeFileSize(Eval("FileSize")) %>'></asp:Label>
    </ItemTemplate>
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    <ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" />
</telerik:GridTemplateColumn>

As you can see, FileSize TemplateColumn is disabled and I am using FileSizeChange instead.

FileSize string is like (213435) -> this number shows us bytes. FileSizeChange is like (231 MB)/

How can I write filtering for both Online and FileSizeChange GridTemplateColumns?

Answer 1

In order to use filtering on a Template column you need to set the DataField and add the datafield to the DataKeyNames

eg:

<telerik:RadGrid ID="RadGrid1" runat="server" AutoGenerateColumns="false" AllowFilteringByColumn="True">
    <MasterTableView DataKeyNames="ID">
        <Columns> 
            <telerik:GridTemplateColumn DataField="ID" FilterControlAltText="Filter Online column" HeaderText="Online" UniqueName="Online">
                <ItemTemplate>
                    <asp:CheckBox ID="chkOnline" runat="server" Checked='<%# CheckForOnline(Eval("ID")) %>' Enabled="False" />
                </ItemTemplate>
                <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
                <ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="100px" />
            </telerik:GridTemplateColumn>
...
etc, etc