How do I Inherit a WPF DataGrid Cell Style when programmatically adding a DataTrigger?

Question

I'm writing a WPF application which makes use of the DataGrid control. I'm using the MaterialDesign theme to style the application and this gives a nice look and feel.

However for complex reasons I wont go into here I'm required to add the columns into the dataGrid programmatically. For some of the columns I'm also styling the columns to highlight pass / fail in red. When I do this I loose 'some of the styling' provided by material design for that columns. Namely the Horizontal and Vertical alignment.

The code to the above is as follows:

            // Define Setter
            Setter setterResultFail = new Setter();
            setterResultFail.Property = DataGridCell.BackgroundProperty;
            setterResultFail.Value = Brushes.Red;

            // Create a column for the Site.
            var currentColumn = new DataGridTextColumn();
            currentColumn.Header = "Device #";
            currentColumn.Binding = new Binding("Device");
            ResultsDataGrid.Columns.Add(currentColumn);

            // Create a column for the Site.
            currentColumn = new DataGridTextColumn();
            currentColumn.Header = "Site";
            currentColumn.Binding = new Binding("Site");
            ResultsDataGrid.Columns.Add(currentColumn);

            // Create a column for the Pass Fail.
            currentColumn = new DataGridTextColumn();
            currentColumn.Header = "Pass Fail";
            currentColumn.Binding = new Binding("PassFail") { Converter = new BooleanToPassFailConverter() };

            // Create cellstyle to make the cell 'red' when the PassFail value is False. ( this is done via a data trigger )
            cellStyle = new Style(typeof(DataGridCell));

            // Define First DataTrigger that sets a CELL red if the value is a fail.
            dataTrigger = new DataTrigger();
            dataTrigger.Value = "False";
            dataTrigger.Binding = new Binding("PassFail");            
            dataTrigger.Setters.Add(setterResultFail);

            // Add the data-triggers to the cell style.
            cellStyle.Triggers.Clear();
            cellStyle.Triggers.Add(dataTrigger);

            // Apply the newly created cell style.
            currentColumn.CellStyle = cellStyle;

            ResultsDataGrid.Columns.Add(currentColumn);

Clearly the new cellStyle is used instead of the MaterialDesign style. I've tried setting the values for vertical / horizontal manually but I can't get it to look correct:

            Setter setterTextContentHorizonalAlignment = new Setter();
            setterTextContentHorizonalAlignment.Property = DataGridCell.HorizontalContentAlignmentProperty;
            setterTextContentHorizonalAlignment.Value = HorizontalAlignment.Center;

            Setter setterTextContentVerticalAlignment = new Setter();
            setterTextContentVerticalAlignment.Property = DataGridCell.VerticalContentAlignmentProperty;
            setterTextContentVerticalAlignment.Value = VerticalAlignment.Center;

            Setter setterTextHorizontalAlignment = new Setter();
            setterTextHorizontalAlignment.Property = DataGridCell.HorizontalAlignmentProperty;
            setterTextHorizontalAlignment.Value = HorizontalAlignment.Center;

            Setter setterTextVerticalAlignment = new Setter();
            setterTextVerticalAlignment.Property = DataGridCell.VerticalAlignmentProperty;
            setterTextVerticalAlignment.Value = VerticalAlignment.Center;

            cellStyle.Setters.Add(setterTextContentHorizonalAlignment);
            cellStyle.Setters.Add(setterTextContentVerticalAlignment);
            cellStyle.Setters.Add(setterTextHorizontalAlignment);
            cellStyle.Setters.Add(setterTextVerticalAlignment);

Is there a way I can add to the style rather than replace it...similar to the BasedOn approch in XAML?

score 0 · Answer 1 · answered Mar 23 '18 at 09:55

After much wasting of time on this question I came across Danny Beckett's similar question and King King's answer. By using his answer and applying it to the specific cell I was having trouble with it fixed the issue:King King's answer

     // Create a column for the Pass Fail.
     currentColumn = new DataGridTextColumn();
     currentColumn.Header = "Pass Fail";
     currentColumn.Binding = new Binding("PassFail") { Converter = new BooleanToPassFailConverter() };

     // Create cellstyle to make the cell 'red' when the PassFail value is False. ( this is done via a data trigger )
     cellStyle = new Style(typeof(DataGridCell));

     // Define First DataTrigger that sets a CELL red if the value is a fail.
     dataTrigger = new DataTrigger();
     dataTrigger.Value = "False";
     dataTrigger.Binding = new Binding("PassFail");
     dataTrigger.Setters.Add(setterResultFail);

     // Add the data-triggers to the cell style.
     cellStyle.Triggers.Clear();
     cellStyle.Triggers.Add(dataTrigger);

     //root visual of the ControlTemplate for DataGridCell is a Border
     var border = new FrameworkElementFactory(typeof(Border));
     border.SetBinding(Border.BorderBrushProperty, new Binding("BorderBrush")
     {
           RelativeSource = RelativeSource.TemplatedParent
     });

     border.SetBinding(Border.BackgroundProperty, new Binding("Background") { RelativeSource = RelativeSource.TemplatedParent });
     border.SetBinding(Border.BorderThicknessProperty, new Binding("BorderThickness") { RelativeSource = RelativeSource.TemplatedParent });
     border.SetValue(SnapsToDevicePixelsProperty, true);

     //the only child visual of the border is the ContentPresenter
     var contentPresenter = new FrameworkElementFactory(typeof(ContentPresenter));
     contentPresenter.SetBinding(SnapsToDevicePixelsProperty, new Binding("SnapsToDevicePixelsProperty") { RelativeSource = RelativeSource.TemplatedParent });
     contentPresenter.SetBinding(VerticalAlignmentProperty, new Binding("VerticalContentAlignment") { RelativeSource = RelativeSource.TemplatedParent });
     contentPresenter.SetBinding(HorizontalAlignmentProperty, new Binding("HorizontalContentAlignment") { RelativeSource = RelativeSource.TemplatedParent });
     //add the child visual to the root visual
     border.AppendChild(contentPresenter);

     //here is the instance of ControlTemplate for DataGridCell
     var template = new ControlTemplate(typeof(DataGridCell));
     template.VisualTree = border;

     //define the style
     cellStyle.Setters.Add(new Setter(TemplateProperty, template));
     cellStyle.Setters.Add(new Setter(VerticalContentAlignmentProperty, VerticalAlignment.Center));
     cellStyle.Setters.Add(new Setter(HorizontalContentAlignmentProperty, HorizontalAlignment.Center));

     // Apply the newly created cell style.
     currentColumn.CellStyle = cellStyle;

How do I Inherit a WPF DataGrid Cell Style when programmatically adding a DataTrigger?

1 Answers1