Is it possible to create and set styles and/or template for combobox in c# only?

Reinder Weenink 20 Reputation points
2024-04-12T14:03:37.46+00:00

Hi,

I'm trying to setup a app frontend in C# only. I'm more practiced with c# then XAML, but also have the feeling that I can make the app windows/pages more parametric in this way.

Thus far I'm succeeding in this, however when I tried setting up comboboxes in this way I encountered problems which I dont understand and cant find info over.

Is it possible to setup custom combobox styles/visuals in c# only?

If yes, is there documentation or any samples for this?

Below a hyperlink to a website of microsoft with samples in XAML to give an idea of the things i would like to setup.

Shape,

background color,

selecteditem color,

etc.

https://learn.microsoft.com/en-us/dotnet/desktop/wpf/controls/how-to-create-apply-template?view=netdesktop-8.0

Thanks in advance, Kind regards.

Windows Presentation Foundation
Windows Presentation Foundation
A part of the .NET Framework that provides a unified programming model for building line-of-business desktop applications on Windows.
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C#
C#
An object-oriented and type-safe programming language that has its roots in the C family of languages and includes support for component-oriented programming.
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Accepted answer
  1. Hui Liu-MSFT 38,256 Reputation points Microsoft Vendor
    2024-04-15T07:45:14.6333333+00:00

    Hi,@Reinder Weenink. Welcome to Microsoft Q&A.

    It's difficult to create and style a ComboBox in C# code without using XAML.

    You can customize the appearance and behavior of a ComboBox simply by modifying its properties and the ControlTemplate in code-behind. But when more attributes are involved, a lot of errors appear

    It can be more verbose and less intuitive than defining styles and templates in XAML.

    I tried copying styles from xaml to codebedhind without success.
    my steps: create a ComboBox in xaml designer ->right click the ComboBox ->Select Edit Template->select Edit a Copy... ->select OK to ComboBoxStyle ->edit the generate style (Simplify the code regarding colors)->then try to realize the same effect in codebedhind

    
       private void ApplyCustomComboBoxStyle()
       {
           // FocusVisual style
           Style focusVisualStyle = new Style(typeof(Control));
           focusVisualStyle.Setters.Add(new Setter(Control.TemplateProperty, new ControlTemplate(typeof(Control))));
           Application.Current.Resources.Add(SystemColors.ControlTextBrushKey, Brushes.Black);
           Application.Current.Resources.Add("FocusVisual", focusVisualStyle);
    
           // ComboBoxEditableTextBox style
           Style comboBoxEditableTextBoxStyle = new Style(typeof(TextBox));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.OverridesDefaultStyleProperty, true));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.AllowDropProperty, true));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.MinWidthProperty, 0d));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.MinHeightProperty, 0d));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.FocusVisualStyleProperty, null));
           //comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.ScrollViewer.PanningModeProperty, PanningMode.VerticalFirst));
          // comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.StylusIsFlicksEnabledProperty, false));
           comboBoxEditableTextBoxStyle.Setters.Add(new Setter(TextBox.TemplateProperty, new ControlTemplate(typeof(TextBox))));
    
           // ComboBoxToggleButton style
           Style comboBoxToggleButtonStyle = new Style(typeof(ToggleButton));
           comboBoxToggleButtonStyle.Setters.Add(new Setter(ToggleButton.OverridesDefaultStyleProperty, true));
           comboBoxToggleButtonStyle.Setters.Add(new Setter(ToggleButton.IsTabStopProperty, false));
           comboBoxToggleButtonStyle.Setters.Add(new Setter(ToggleButton.FocusableProperty, false));
           comboBoxToggleButtonStyle.Setters.Add(new Setter(ToggleButton.ClickModeProperty, ClickMode.Press));
           comboBoxToggleButtonStyle.Setters.Add(new Setter(ToggleButton.TemplateProperty, CreateComboBoxToggleButtonTemplate()));
    
           // ComboBoxTemplate
           ControlTemplate comboBoxTemplate = CreateComboBoxTemplate();
           Application.Current.Resources.Add("ComboBoxTemplate", comboBoxTemplate);
    
           // ComboBoxStyle1
           Style comboBoxStyle1 = new Style(typeof(ComboBox));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.FocusVisualStyleProperty, Application.Current.Resources["FocusVisual"]));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.BackgroundProperty, Brushes.Pink));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.BorderBrushProperty, Brushes.Purple));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.ForegroundProperty, SystemColors.WindowTextBrush));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.BorderThicknessProperty, new Thickness(1)));
           comboBoxStyle1.Setters.Add(new Setter(ScrollViewer.HorizontalScrollBarVisibilityProperty, ScrollBarVisibility.Auto));
           comboBoxStyle1.Setters.Add(new Setter(ScrollViewer.VerticalScrollBarVisibilityProperty, ScrollBarVisibility.Auto));
           comboBoxStyle1.Setters.Add(new Setter(ScrollViewer.CanContentScrollProperty, true));
           comboBoxStyle1.Setters.Add(new Setter(ScrollViewer.PanningModeProperty, PanningMode.Both));
           comboBoxStyle1.Setters.Add(new Setter(Stylus.IsFlicksEnabledProperty, false));
           comboBoxStyle1.Setters.Add(new Setter(ComboBox.TemplateProperty, comboBoxTemplate));
    
           // Apply style to ComboBox
           ComboBox comboBox = new ComboBox();
           comboBox.Style = comboBoxStyle1;
           comboBox.Items.Add(new ComboBoxItem() { Content = "1" });
           comboBox.Items.Add(new ComboBoxItem() { Content = "2" });
           comboBox.Items.Add(new ComboBoxItem() { Content = "3" });
    
           // Add ComboBox to the StackPanel
           grid.Children.Add(comboBox);
       }
    
       private ControlTemplate CreateComboBoxToggleButtonTemplate()
       {
           ControlTemplate template = new ControlTemplate(typeof(ToggleButton));
           FrameworkElementFactory border = new FrameworkElementFactory(typeof(Border));
           border.Name = "templateRoot";
           border.SetValue(Border.BackgroundProperty, Brushes.Red);
           border.SetValue(Border.BorderBrushProperty, Brushes.Blue);
           border.SetValue(Border.BorderThicknessProperty, new Thickness(1));
           border.SetValue(Border.SnapsToDevicePixelsProperty, true);
    
           FrameworkElementFactory splitBorder = new FrameworkElementFactory(typeof(Border));
           splitBorder.SetValue(Border.BackgroundProperty, Brushes.Gray);
           splitBorder.SetValue(Border.BorderBrushProperty, Brushes.Transparent);
           splitBorder.SetValue(Border.BorderThicknessProperty, new Thickness(1));
           splitBorder.SetValue(Border.HorizontalAlignmentProperty, HorizontalAlignment.Right);
           splitBorder.SetValue(Border.MarginProperty, new Thickness(0));
           splitBorder.SetValue(Border.SnapsToDevicePixelsProperty, true);
           splitBorder.SetValue(Border.WidthProperty, SystemParameters.VerticalScrollBarWidth);
    
           FrameworkElementFactory arrow = new FrameworkElementFactory(typeof(Path));
           arrow.SetValue(Path.DataProperty, Geometry.Parse("F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z"));
           arrow.SetValue(Path.FillProperty, Brushes.Gray);
           arrow.SetValue(Path.HorizontalAlignmentProperty, HorizontalAlignment.Center);
           arrow.SetValue(Path.MarginProperty, new Thickness(0));
           arrow.SetValue(Path.VerticalAlignmentProperty, VerticalAlignment.Center);
    
           splitBorder.AppendChild(arrow);
           border.AppendChild(splitBorder);
    
           template.VisualTree = border;
    
           return template;
       }
    
       private ControlTemplate CreateComboBoxTemplate()
       {
           ControlTemplate template = new ControlTemplate(typeof(ComboBox));
           FrameworkElementFactory grid = new FrameworkElementFactory(typeof(Grid));
           grid.Name = "templateRoot";
           grid.SetValue(Grid.SnapsToDevicePixelsProperty, true);
    
           FrameworkElementFactory popup = new FrameworkElementFactory(typeof(Popup));
           popup.Name = "PART_Popup";
           popup.SetValue(Popup.AllowsTransparencyProperty, true);
           popup.SetValue(Popup.IsOpenProperty, new TemplateBindingExtension(ComboBox.IsDropDownOpenProperty));
           popup.SetValue(Popup.MarginProperty, new Thickness(1));
           popup.SetValue(Popup.PlacementProperty, PlacementMode.Bottom);
           popup.SetValue(Popup.PopupAnimationProperty, SystemParameters.ComboBoxPopupAnimation);
          // System.Windows.Controls.Primitives.SystemDropShadowChrome shadow = new System.Windows.Controls.Primitives.SystemDropShadowChrome();
         //  FrameworkElementFactory shadow = new FrameworkElementFactory(typeof(SystemDropShadowChrome));
         //  shadow.Name = "shadow";
          // shadow.SetValue(SystemDropShadowChrome.ColorProperty, Colors.Transparent);
          // shadow.SetValue(SystemDropShadowChrome.MinWidthProperty, new TemplateBindingExtension(grid.ActualWidthProperty));
          // shadow.SetValue(SystemDropShadowChrome.MaxHeightProperty, new TemplateBindingExtension(ComboBox.MaxDropDownHeightProperty));
    
           //FrameworkElementFactory dropDownBorder = new FrameworkElementFactory(typeof(Border));
           //dropDownBorder.Name = "dropDownBorder";
           //dropDownBorder.SetValue(Border.BackgroundProperty, SystemColors.WindowBrush);
           //dropDownBorder.SetValue(Border.BorderBrushProperty, SystemColors.WindowFrameBrush);
           //dropDownBorder.SetValue(Border.BorderThicknessProperty, new Thickness(1));
    
          // FrameworkElementFactory dropDownScrollViewer = new FrameworkElementFactory(typeof(ScrollViewer));
          // dropDownScrollViewer.Name = "DropDownScrollViewer";
    
           FrameworkElementFactory itemsPresenter = new FrameworkElementFactory(typeof(ItemsPresenter));
           itemsPresenter.Name = "ItemsPresenter";
           itemsPresenter.SetValue(KeyboardNavigation.DirectionalNavigationProperty, KeyboardNavigationMode.Contained);
           itemsPresenter.SetValue(UIElement.SnapsToDevicePixelsProperty, new TemplateBindingExtension(UIElement.SnapsToDevicePixelsProperty));
    
          // dropDownScrollViewer.AppendChild(itemsPresenter);
          // dropDownBorder.AppendChild(dropDownScrollViewer);
          // shadow.AppendChild(dropDownBorder);
         //  popup.AppendChild(shadow);
           grid.AppendChild(popup);
    
           FrameworkElementFactory toggleButton = new FrameworkElementFactory(typeof(ToggleButton));
           toggleButton.Name = "toggleButton";
           toggleButton.SetValue(ToggleButton.BackgroundProperty, new TemplateBindingExtension(ComboBox.BackgroundProperty));
           toggleButton.SetValue(ToggleButton.BorderBrushProperty, new TemplateBindingExtension(ComboBox.BorderBrushProperty));
           toggleButton.SetValue(ToggleButton.BorderThicknessProperty, new TemplateBindingExtension(ComboBox.BorderThicknessProperty));
           toggleButton.SetValue(ToggleButton.IsCheckedProperty, new Binding("IsDropDownOpen") { RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent) });
           toggleButton.SetValue(ToggleButton.StyleProperty, new StaticResourceExtension("ComboBoxToggleButton"));
    
           grid.AppendChild(toggleButton);
    
           FrameworkElementFactory contentPresenter = new FrameworkElementFactory(typeof(ContentPresenter));
           contentPresenter.Name = "contentPresenter";
           contentPresenter.SetValue(ContentPresenter.ContentStringFormatProperty, new TemplateBindingExtension(ComboBox.SelectionBoxItemStringFormatProperty));
           contentPresenter.SetValue(ContentPresenter.ContentTemplateProperty, new TemplateBindingExtension(ComboBox.SelectionBoxItemTemplateProperty));
           contentPresenter.SetValue(ContentPresenter.ContentProperty, new TemplateBindingExtension(ComboBox.SelectionBoxItemProperty));
           contentPresenter.SetValue(ContentPresenter.ContentTemplateSelectorProperty, new TemplateBindingExtension(ComboBox.ItemTemplateSelectorProperty));
           contentPresenter.SetValue(FrameworkElement.HorizontalAlignmentProperty, new TemplateBindingExtension(Control.HorizontalContentAlignmentProperty));
           contentPresenter.SetValue(FrameworkElement.MarginProperty, new TemplateBindingExtension(Control.PaddingProperty));
           contentPresenter.SetValue(FrameworkElement.SnapsToDevicePixelsProperty, new TemplateBindingExtension(UIElement.SnapsToDevicePixelsProperty));
           contentPresenter.SetValue(FrameworkElement.VerticalAlignmentProperty, new TemplateBindingExtension(Control.VerticalContentAlignmentProperty));
    
           grid.AppendChild(contentPresenter);
    
           template.VisualTree = grid;
    
           //Trigger hasDropShadowTrigger = new Trigger() { Property = ComboBox.HasDropShadowProperty, Value = true };
           //hasDropShadowTrigger.Setters.Add(new Setter(Control.MarginProperty, new Thickness(0, 0, 5, 5)) { TargetName = "shadow" });
           //hasDropShadowTrigger.Setters.Add(new Setter(SystemDropShadowChrome.ColorProperty, "#71000000") { TargetName = "shadow" });
           //template.Triggers.Add(hasDropShadowTrigger);
    
           //Trigger hasItemsTrigger = new Trigger() { Property = ItemsControl.HasItemsProperty, Value = false };
           //hasItemsTrigger.Setters.Add(new Setter(FrameworkElement.HeightProperty, 95d) { TargetName = "dropDownBorder" });
           //template.Triggers.Add(hasItemsTrigger);
    
           MultiTrigger isGroupingTrigger = new MultiTrigger();
           isGroupingTrigger.Conditions.Add(new Condition(ItemsControl.IsGroupingProperty, true));
           isGroupingTrigger.Conditions.Add(new Condition(VirtualizingPanel.IsVirtualizingWhenGroupingProperty, false));
        //   isGroupingTrigger.Setters.Add(new Setter(ScrollViewer.CanContentScrollProperty, false) { TargetName = "DropDownScrollViewer" });
           template.Triggers.Add(isGroupingTrigger);
    
         //  Trigger canContentScrollTrigger = new Trigger() { Property = ScrollViewer.CanContentScrollProperty, SourceName = "DropDownScrollViewer", Value = false };
         //  canContentScrollTrigger.Setters.Add(new Setter(Canvas.TopProperty, new Binding("VerticalOffset") { ElementName = "DropDownScrollViewer" }) { TargetName = "opaqueRect" });
          // canContentScrollTrigger.Setters.Add(new Setter(Canvas.LeftProperty, new Binding("HorizontalOffset") { ElementName = "DropDownScrollViewer" }) { TargetName = "opaqueRect" });
          // template.Triggers.Add(canContentScrollTrigger);
    
           return template;
       }
    
       public void CustomComboBox()
       {
           // Create a style for the ComboBox
           Style comboBoxStyle = new Style(typeof(ComboBox));
    
           // Setters for various properties of the ComboBox
           comboBoxStyle.Setters.Add(new Setter(BackgroundProperty, Brushes.LightGray));
           comboBoxStyle.Setters.Add(new Setter(BorderBrushProperty, Brushes.Gray));
           comboBoxStyle.Setters.Add(new Setter(BorderThicknessProperty, new Thickness(1)));
           comboBoxStyle.Setters.Add(new Setter(ForegroundProperty, Brushes.Black));
    
           // Create a ControlTemplate for the ComboBox
           ControlTemplate comboBoxTemplate = new ControlTemplate(typeof(ComboBox));
    
           // Create the main Grid in the ControlTemplate
           FrameworkElementFactory gridFactory = new FrameworkElementFactory(typeof(Grid));
    
           // Create the ToggleButton for the ComboBox
           FrameworkElementFactory toggleButtonFactory = new FrameworkElementFactory(typeof(ToggleButton));
           toggleButtonFactory.SetValue(ToggleButton.BackgroundProperty, Brushes.Transparent);
           toggleButtonFactory.SetValue(ToggleButton.BorderThicknessProperty, new Thickness(0));
           toggleButtonFactory.SetValue(ToggleButton.TemplateProperty, GetCustomToggleButtonTemplate());
    
           // Add the ToggleButton to the main Grid
           gridFactory.AppendChild(toggleButtonFactory);
    
           // Set the ControlTemplate's VisualTree
           comboBoxTemplate.VisualTree = gridFactory;
    
           // Set the ComboBox's ControlTemplate
           comboBoxStyle.Setters.Add(new Setter(TemplateProperty, comboBoxTemplate));
    
           // Set the style to the ComboBox
           this.Style = comboBoxStyle;
       }
    
       private ControlTemplate GetCustomToggleButtonTemplate()
       {
           // Create a ControlTemplate for the ToggleButton
           ControlTemplate toggleButtonTemplate = new ControlTemplate(typeof(ToggleButton));
    
           // Create the main Grid in the ControlTemplate
           FrameworkElementFactory gridFactory = new FrameworkElementFactory(typeof(Grid));
    
           // Set the Grid's properties
    
           // Create the Border for the ToggleButton
           FrameworkElementFactory borderFactory = new FrameworkElementFactory(typeof(Border));
           borderFactory.SetValue(Border.BackgroundProperty, Brushes.Transparent);
           borderFactory.SetValue(Border.BorderThicknessProperty, new Thickness(0));
    
           // Create the ContentPresenter for the ToggleButton
           FrameworkElementFactory contentPresenterFactory = new FrameworkElementFactory(typeof(ContentPresenter));
    
           // Add the ContentPresenter to the Border
           borderFactory.AppendChild(contentPresenterFactory);
    
           // Add the Border to the main Grid
           gridFactory.AppendChild(borderFactory);
    
           // Set the ControlTemplate's VisualTree
           toggleButtonTemplate.VisualTree = gridFactory;
    
           return toggleButtonTemplate;
       }
    
    
    

    It is recommended to use xaml code and c# to set styles and templates.


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