How to change IsReadOnly by Trigger - wpf

Question

can anybody enlight me way the following doesn't work
i'm using the mvvm pattern
after executing my code i'm still able to check and uncheck the Checkboxes in my DataGridCheckBoxColumn
Property (part of my ViewModel)
public bool noCheckPermission
{
get { return false; } // just as example
}
Xaml (my View no code behind)
<DataGrid Height="300" AutoGenerateColumns="False" SelectionMode="Single"
ItemsSource="{Binding Itemlist, UpdateSourceTrigger=PropertyChanged}">
<DataGrid.Resources>
<Style TargetType="{x:Type DataGridCheckBoxColumn}">
<Style.Triggers>
<DataTrigger Binding="{Binding noCheckPermission}" Value="False">
<Setter Property="IsReadOnly" Value="True"/>
</DataTrigger>
<DataTrigger Binding="{Binding noCheckPermission}" Value="True">
<Setter Property="IsReadOnly" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</DataGrid.Resources>
<DataGrid.Columns>
<DataGridCheckBoxColumn Width="60"
Header="Freigabe" Binding="{Binding FreigegebenL}" CanUserReorder="False">
</DataGridCheckBoxColumn>
</DataGrid.Columns>
</DataGrid>
Edit:
after doing what blindmeis and Will suggested. I got this as my current XAML
<DataGrid Height="300" Margin="12" AutoGenerateColumns="False" CanUserAddRows="False" CanUserDeleteRows="False"
CanUserResizeColumns="False" CanUserResizeRows="False" CanUserReorderColumns="False"
x:Name="grd" ItemsSource="{Binding Itemlist, UpdateSourceTrigger=PropertyChanged}"
SelectedItem="{Binding selectedItem, UpdateSourceTrigger=PropertyChanged}" SelectionMode="Single" SelectionChanged="DataGrid_SelectionChanged" TabIndex="2">
<DataGrid.Columns>
<DataGridCheckBoxColumn Width="60" IsReadOnly="{Binding DataContext, Path=noCheckPermission, ElementName=grd}" Binding="{Binding FreigegebenL}"
Header="Freigabe" CanUserReorder="False">
</DataGridCheckBoxColumn>
</DataGrid.Columns>
</DataGrid>
and this as Error in my Output Window:
System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=noCheckPermission; DataItem=null; target element is 'DataGridCheckBoxColumn' (HashCode=35155182); target property is 'IsReadOnly' (type 'Boolean')

Answer 1

first
i noticed that my property was in the wrong VM (it was in the Child VM which are my rows) fixing this doesn't solved my problem
finally
after reading this article i was able to solve it
in condensed form
class
public class BindingProxy : Freezable
{
#region Overrides of Freezable
protected override Freezable CreateInstanceCore()
{
return new BindingProxy();
}
#endregion
public object Data
{
get { return (object)GetValue(DataProperty); }
set { SetValue(DataProperty, value); }
}
// Using a DependencyProperty as the backing store for Data. This enables animation, styling, binding, etc...
public static readonly DependencyProperty DataProperty =
DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
}
XAML
Resources
<DataGrid.Resources>
<local:BindingProxy x:Key="proxy" Data="{Binding}" />
</DataGrid.Resources>
Column
<DataGridCheckBoxColumn Width="60" Header="Freigabe" CanUserReorder="False"
IsReadOnly="{Binding Data.noCheckPermission, Source={StaticResource proxy}}"
Binding="{Binding FreigegebenL}"/>

Answer 2

if you just want the DataGridCheckBoxColumn to be readonly, you should add your style to your DataGridCheckBoxColumn.
<DataGrid Height="300" AutoGenerateColumns="False" SelectionMode="Single"
x:Name="grd"
ItemsSource="{Binding Itemlist, UpdateSourceTrigger=PropertyChanged}">
<DataGrid.Columns>
<DataGridCheckBoxColumn Width="60"
Header="Freigabe" Binding="{Binding FreigegebenL}" CanUserReorder="False">
<DataGridCheckBoxColumn.Style>
<Style TargetType="{x:Type DataGridCheckBoxColumn}">
<Style.Triggers>
<DataTrigger Binding="{Binding DataContext.noCheckPermission, ElementName=grd}" Value="False">
<Setter Property="IsReadOnly" Value="True"/>
</DataTrigger>
<DataTrigger Binding="{Binding DataContext.noCheckPermission, ElementName=grd}" Value="True">
<Setter Property="IsReadOnly" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</DataGridCheckBoxColumn.Style>
</DataGridCheckBoxColumn>
</DataGrid.Columns>
</DataGrid>