WPF DataGrid toggle selection mode & Button in CellTemplate

Question

I'm building a POS application, and I want the end user to be able to have a toggle selection mode for the datagrid, I.E. they can click on multiple rows and each clicked item will accumulate on the SelectedItems property - also clicking on a row that was already selected will deselect the row. I found this code in another stackoverflow question:

<DataGrid.Resources>
    <Style TargetType="{x:Type DataGridCell}">
        <EventSetter Event="PreviewMouseLeftButtonDown" Handler="DoCheckRow" />
    </Style>
</DataGrid.Resources>

public void DoCheckRow(object sender, MouseButtonEventArgs e)
{
    DataGridCell cell = sender as DataGridCell;
    if (cell != null && !cell.IsEditing)
    {
        DataGridRow row = VisualHelpers.TryFindParent<DataGridRow>(cell);
        if (row != null)
        {
            row.IsSelected = !row.IsSelected;
            e.Handled = true;
            Debug.WriteLine(sender);
        }
    }
}

That effectively gives me what I want as far as the toggle selection mode, however, when I add a button as a CellTemplate, the buttons command isn't fired when clicked because I'm setting e.Handled = true; in the above code which stops the event bubble. Is there a way that I can accommodate both?

score 1 · Answer 1 · answered Aug 24 '12 at 15:24

1

Maybe you can try putting an AttachedBehavior on your button? This way you take command out of the picture and handle the click event in the AttachedBehavior.

answered Aug 24 '12 at 15:24

Big Daddy

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Good suggestion. I tried an attached behavior as well as just handling the Click event. It doesn't get called. – Chris Klepeis Aug 24 '12 at 15:32
1

Have a look at this: http://stackoverflow.com/questions/2445106/wpf-two-commands-handlers-one-command – Big Daddy Aug 24 '12 at 16:05
Thanks for point me in the right direction! I was able to solve it using hittesting and some helper functions to find the visual child / parent. See my answer – Chris Klepeis Aug 24 '12 at 16:54

score 1 · Answer 2 · answered Jan 26 '16 at 18:22

You could also do this with an checkbox that will toggle selection on corrosponding row.

<DataGrid.RowHeaderTemplate>
   <DataTemplate>
      <CheckBox IsChecked="{Binding Path=IsSelected, Mode=TwoWay,
                           RelativeSource={RelativeSource FindAncestor,
                           AncestorType={x:Type DataGridRow}}}"/>
   </DataTemplate>
</DataGrid.RowHeaderTemplate>

score 0 · Accepted Answer · answered Aug 24 '12 at 16:55

I was able to solve it by using some helper functions to find the visual child / parent and some hit testing:

public void DoCheckRow(object sender, MouseButtonEventArgs e)
{
    DataGridCell cell = sender as DataGridCell;
    if (cell != null && !cell.IsEditing)
    {
        DataGridRow row = VisualHelpers.TryFindParent<DataGridRow>(cell);
        if (row != null)
        {
            Button button = VisualHelpers.FindVisualChild<Button>(cell, "ViewButton");

            if (button != null)
            {
                HitTestResult result = VisualTreeHelper.HitTest(button, e.GetPosition(cell));

                if (result != null)
                {
                    // execute button and do not select / deselect row
                    button.Command.Execute(row.DataContext);
                    e.Handled = true;
                    return;
                }
            }

            row.IsSelected = !row.IsSelected;
            e.Handled = true;
        }
    }
}

Granted its not the most elegant solution, but it works with the MVVM pattern that I use.

WPF DataGrid toggle selection mode & Button in CellTemplate

3 Answers3

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