WPF Changing column width at runtime

c#, wpf, xaml

Solution

Your XAML file should looks like this:

<Grid.ColumnDefinitions>
        <ColumnDefinition />
        <ColumnDefinition />
        <ColumnDefinition Name="thirdColumn" Width="0"/>
    </Grid.ColumnDefinitions>
</Grid>

And selected datagrid event scope in your code behind file:

GridLength g2 = new GridLength(2, GridUnitType.Star);
thirdColumn.Width = g2;

Problem

I have an WPF application that contains a grid. The grid is split into 3 columns with the 3rd grid having zero width upon loading. I have two datagrids in the other two columns. When the selected item in one of the datagrid changes the other datagrid changes it display values, i.e. a master detail template. This all works fine. There is one value in the datagrid that if selected I wish this 3rd column to changes its width from zero to 2*. I don't know how to do this? EDIT I wish to achieve this through XAML. I have been looking at data triggers & value converters. I written some code below quickly to test. I have read that setting the column to width=0 there is probably higher on the dependency property setting precedence list. Is there anyway to do this or will I need to use code behind? ``` <Grid> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="2*"/> <ColumnDefinition Width="0"/> </Grid.ColumnDefinitions> <DataGrid Grid.Column="0" ItemsSource="{Binding OrderList}" SelectedItem="{Binding OrderSelected}" AutoGenerateColumns="True"> </DataGrid> <TextBox Grid.Column="1" Text="{Binding OrderSelected.Name}"> </TextBox> <Grid x:Name="columnHideSeek" Grid.Column="2" Background="Blue"> <Grid.Style> <Style> <Style.Triggers> <DataTrigger Binding="{Binding OrderSelected.Name}" Value="Mark"> <Setter Property="Grid.Width" Value="10"/> </DataTrigger> </Style.Triggers> </Style> </Grid.Style> </Grid> </Grid> ```

Original source