c# - 以编程方式在 WPF 中创建一个网格作为模板

Question

我想以编程方式创建具有样式的基本用户控件。在这种样式中，我想添加一个 Grid(没问题)，但我无法向该网格添加列定义。

我的示例代码是

ControlTemplate templ = new ControlTemplate();
FrameworkElementFactory mainPanel = new FrameworkElementFactory(typeof(DockPanel));
mainPanel.SetValue(DockPanel.LastChildFillProperty, true);

FrameworkElementFactory headerPanel = new FrameworkElementFactory(typeof(StackPanel));
headerPanel.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal);
headerPanel.SetValue(DockPanel.DockProperty, Dock.Top);
mainPanel.AppendChild(headerPanel);

FrameworkElementFactory headerImg = new FrameworkElementFactory(typeof(Image));
headerImg.SetValue(Image.MarginProperty, new Thickness(5));
headerImg.SetValue(Image.HeightProperty, 32d);
headerImg.SetBinding(Image.SourceProperty, new Binding("ElementImage") { RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent) });
headerPanel.AppendChild(headerImg);

FrameworkElementFactory headerTitle = new FrameworkElementFactory(typeof(TextBlock));
headerTitle.SetValue(TextBlock.FontSizeProperty, 16d);
headerTitle.SetValue(TextBlock.VerticalAlignmentProperty, VerticalAlignment.Center);
headerTitle.SetBinding(TextBlock.TextProperty, new Binding("Title") { RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent) });
headerPanel.AppendChild(headerTitle);

FrameworkElementFactory mainGrid = new FrameworkElementFactory(typeof(Grid));
FrameworkElementFactory c1 = new FrameworkElementFactory(typeof(ColumnDefinition));
c1.SetValue(ColumnDefinition.WidthProperty, new GridLength(1, GridUnitType.Star));
FrameworkElementFactory c2 = new FrameworkElementFactory(typeof(ColumnDefinition));
c2.SetValue(ColumnDefinition.WidthProperty, new GridLength(1, GridUnitType.Auto));
FrameworkElementFactory c3 = new FrameworkElementFactory(typeof(ColumnDefinition));
c3.SetValue(ColumnDefinition.WidthProperty, new GridLength(3, GridUnitType.Star));
FrameworkElementFactory colDefinitions = new FrameworkElementFactory(typeof(ColumnDefinitionCollection));
colDefinitions.AppendChild(c1);
colDefinitions.AppendChild(c2);
colDefinitions.AppendChild(c3);
mainGrid.AppendChild(colDefinitions);

mainPanel.AppendChild(mainGrid);

FrameworkElementFactory content = new FrameworkElementFactory(typeof(ContentPresenter));
content.SetBinding(ContentPresenter.ContentProperty, new Binding() { RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent), Path = new PropertyPath("Content") });
mainGrid.AppendChild(content);

templ.VisualTree = mainPanel;
Style mainStyle = new Style();
mainStyle.Setters.Add(new Setter(UserControl.TemplateProperty, templ));
this.Style = mainStyle;

但是创建类型为 ColumnDefinitionCollection 的 FrameworkElementFactory 将抛出异常 “'ColumnDefinitionCollection' 类型必须派生自 FrameworkElement、FrameworkContentElement 或 Visual3D。”

谁能帮帮我？

Answer 1

FrameworkElementFactory 有一些自定义逻辑来处理 Grid 中的 ColumnDefinitions 和 RowDefinitions。对于这些值，您将它们视为工厂树中的 child ，例如:

FrameworkElementFactory gridFactory = new FrameworkElementFactory(typeof(Grid));

var column1 = new FrameworkElementFactory(typeof(ColumnDefinition));
column1.SetValue(ColumnDefinition.WidthProperty, new GridLength(1, GridUnitType.Auto));

var column2 = new FrameworkElementFactory(typeof(ColumnDefinition));
column2.SetValue(ColumnDefinition.WidthProperty, new GridLength(1, GridUnitType.Star));

gridFactory.AppendChild(column1);
gridFactory.AppendChild(column2);