Я пытался решить мой предыдущийвопрос с ручной привязкойWidth собственностьDataGridTextColumn вот первая версия моего кода XAML.

   <DataGrid AutoGenerateColumns="False" Background="White" ItemsSource="{Binding Items, Mode=OneWay}" 
              HorizontalGridLinesBrush="Silver" VerticalGridLinesBrush="Silver"
              Margin="332,10,10,10" CanUserAddRows="False" CanUserDeleteRows="False"
              x:Name="myDataGrid" ColumnWidth="*">
        <DataGrid.Columns>
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, RelativeSource={RelativeSource AncestorType=DataGrid}}" IsReadOnly="True" Header="Column1" Binding="{Binding Value1, Mode=OneWay}" />
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, RelativeSource={RelativeSource AncestorType=DataGrid}}" IsReadOnly="True" Header="Column2" Binding="{Binding Value2, Mode=OneWay}"/>
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, RelativeSource={RelativeSource AncestorType=DataGrid}}" IsReadOnly="True" Header="Column3" Binding="{Binding Value3, Mode=OneWay}"/>
        </DataGrid.Columns>
    </DataGrid>

После небольшого исследования я нашел этоПочта это, кажется, дает ответ на мою проблему, и я обновил свойDataGrid код.

   <DataGrid AutoGenerateColumns="False" Background="White" ItemsSource="{Binding Items, Mode=OneWay}" 
              HorizontalGridLinesBrush="Silver" VerticalGridLinesBrush="Silver"
              Margin="332,10,10,10" CanUserAddRows="False" CanUserDeleteRows="False"
              x:Name="myDataGrid" ColumnWidth="*">
        <DataGrid.Columns>
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, Source={x:Reference Name=myDataGrid}}" IsReadOnly="True" Header="Column1" Binding="{Binding Value1, Mode=OneWay}" />
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, Source={x:Reference Name=myDataGrid}}" IsReadOnly="True" Header="Column2" Binding="{Binding Value2, Mode=OneWay}"/>
            <DataGridTextColumn Width="{Binding Path=ActualWidth, Converter={StaticResource ResourceKey=WidthValueConverter}, Source={x:Reference Name=myDataGrid}}" IsReadOnly="True" Header="Column3" Binding="{Binding Value3, Mode=OneWay}"/>
        </DataGrid.Columns>
    </DataGrid>

но теперь я получаю это исключение XamlParseException

Cannot call MarkupExtension.ProvideValue because of a cyclical dependency. Properties inside a 
MarkupExtension cannot reference objects that reference the result of the MarkupExtension. 
The affected MarkupExtensions are:
'System.Windows.Data.Binding' Line number '37' and line position '37'.
'System.Windows.Data.Binding' Line number '38' and line position '37'.
'System.Windows.Data.Binding' Line number '39' and line position '37'.

Так как я могу связатьWidth свойствоDataGridColumn кActualWidth собственность его родителяDataGrid