How change visibility of column in selected row?

Question

When the user selects a row, I would like to display a button at the end of the selected row. Do you have an idea how to do it?

I tried it like this:

<DataGrid Name="Grid" ItemsSource="{Binding Data}" AutoGenerateColumns="False">
   <DataGrid.ItemContainerStyle>
      <Style TargetType="DataGridRow">
         <EventSetter Event="MouseDoubleClick" Handler="Row_DoubleClick"/>
      </Style>
   </DataGrid.ItemContainerStyle>
   <!-- ... -->
   <Button Grid.Column="4" Name="ButtonAssign" Visibility= "Hidden" Content="Assign" Click="btnAssign_Click"/>
   <!-- ... -->

private void Row_DoubleClick(object sender, MouseButtonEventArgs e)
{
   var row = (DataGridRow)sender;

   //I don't know how to find the button on the row in here. This doesn't work:
   var buttonAssign = row.FindName("ButtonAssign");
   //buttonAssign is always NULL :-(
   if (buttonAssign != null)
   {
      ((Button)buttonAssign).Visibility = Visibility.Visible;
   }

   ((RowItemModel)row.Item).ButtonAssignVisibility = Visibility.Hidden;
}

Can you help me please?

Answer 1

You can bind the Visibility of the button to the IsSelected property of the parent DataGridRow using a RelativeSource binding and an instance the built-it BooleanToVisibilityConverter, e.g.:

Visibility="{Binding IsSelected, RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}, Converter={StaticResource BooleanToVisibilityConverter}}"

The following code provides a simple example incorporating code from your question and comments. Apart from the Visibility binding, you have to create a converter instance in any resource dictionary in scope.

<DataGrid ...>
   <DataGrid.Resources>
      <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
   </DataGrid.Resources>
   <DataGrid.Columns>
      <-- ...your other columns. -->
      <DataGridTemplateColumn IsReadOnly="True">
         <DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
               <Grid>
                  <-- ...row and column definitions, other controls. -->
                  <TextBlock Grid.Column="3"
                             Text="{Binding Note}"/>
                  <Button Grid.Column="4"
                          Name="ButtonAssign"
                          Visibility="{Binding IsSelected, RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}, Converter={StaticResource BooleanToVisibilityConverter}}"
                          Content="Assign"
                          Click="btnAssign_Click"/>
               </Grid>
            </DataTemplate>
         </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>
   </DataGrid.Columns>
</DataGrid>