<UserControl x:Class="SilverlightCustomFiltering.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"   
    xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"
    xmlns:telerikGridView="clr-namespace:Telerik.Windows.Controls.GridView;assembly=Telerik.Windows.Controls.GridView"
Width="280">
    <Grid>
        <telerik:RadGridView Name="radGridViewFirstLook" Width="270"  ShowGroupPanel="False" ColumnsWidthMode="Fill" AutoGenerateColumns="False" >
            <telerik:RadGridView.Columns >
                  <telerikGridView:GridViewDataColumn HeaderText="CompanyName"   UniqueName="CompanyName" >
                    <telerik:GridViewColumn.HeaderCellStyle>
                        <Style TargetType="telerikGridView:GridViewHeaderCell">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="telerikGridView:GridViewHeaderCell">
                                        <TextBox   Width="200" TextChanged="TextBoxSearch_TextChanged"  ></TextBox>
                                    </ControlTemplate>
                                </Setter.Value>
                                </Setter>
                        </Style>
                    </telerik:GridViewColumn.HeaderCellStyle>
                </telerikGridView:GridViewDataColumn>
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>

    </Grid>
</UserControl>
