I want to hide the toggle button in Expander as I am new to WPF.

Expander is inside a datagrid template.

here is the code

```
<DataTemplate >
  <StackPanel >

    <Expander  Margin="0,0,0,0"  Width="Auto" Expanded="Expander_Expanded" Collapsed="Expander_Collapsed" PreviewGotKeyboardFocus="Expander_PreviewGotKeyboardFocus" >

      <Expander.Header>
        <Border x:Name="brdr_header" Padding="0" BorderThickness="0,0,0,1" BorderBrush="Black"   CornerRadius="0">

          <Grid x:Name="InnerData" Width="Auto" >
            <Grid.RowDefinitions>
              <RowDefinition  />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>

```