WPF 如何7步写一个badge控件
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首先看一下效果: 任意控件可以附加一个文字在控件的右上角,并带有红色背景 第一步,新建一个空的wpf项目: 第二步,创建一个类,取名为badge: 第三步,将badge的父类设置成 System.Windows.Documents.Adorner public class Badge : Adorner { public Badge(UIElement adornedElement) : base(adornedElement) { } } 里面的adornedElement表示badge后面附加的对象 关于Adorner这个类的说明,微软给了相应的教程 https://learn.microsoft.com/zh-cn/dotnet/desktop/wpf/controls/adorners-overview?view=netframeworkdesktop-4.8 也可以F11查看Adorner类的说明.
第4步,给badge添加一个Content的附加属性: public static readonly DependencyProperty ContentProperty; static Badge() { ContentProperty = DependencyProperty.RegisterAttached("Content", typeof(string), typeof(Badge), new FrameworkPropertyMetadata(string.Empty, new PropertyChangedCallback(ContentChangedCallBack))); } public static string GetContent(DependencyObject obj) public static void SetContent(DependencyObject obj, string value) 第5步,实现content的回调方法: private static void ContentChangedCallBack(DependencyObject d, DependencyPropertyChangedEventArgs e) { var target = d as FrameworkElement; if (target != null) { if (target.IsLoaded) { var layer = AdornerLayer.GetAdornerLayer(target); if (layer != null) { var Adorners = layer.GetAdorners(target); if (Adorners != null) { foreach (var adorner in Adorners) { if (adorner is Badge) { layer.Remove(adorner); } } } layer.Add(new Badge(target)); } } else { target.Loaded += (sender, ae) => { var layer = AdornerLayer.GetAdornerLayer(target); if (layer != null) { var Adorners = layer.GetAdorners(target); if (Adorners != null) { foreach (var adorner in Adorners) { if (adorner is Badge) { layer.Remove(adorner); } } } layer.Add(new Badge(target)); } }; } } } 第6步,重写一下OnRender方法: protected override void OnRender(DrawingContext drawingContext) { var element = this.AdornedElement as FrameworkElement; Rect adornedElementRect = new Rect(element.DesiredSize); var point = adornedElementRect.TopRight; point.X = adornedElementRect.Right - element.Margin.Left - element.Margin.Right; SolidColorBrush renderBrush = new SolidColorBrush(Colors.Red); Pen renderPen = new Pen(new SolidColorBrush(Colors.Red), 0.5); double renderRadius = 5; var content = this.AdornedElement.GetValue(Badge.ContentProperty).ToString(); FormattedText formattedText = new FormattedText(content, CultureInfo.GetCultureInfo("zh-cn"), FlowDirection.LeftToRight, new Typeface("Verdana"), 10, Brushes.White); var textWidth = formattedText.Width; var textHeight = formattedText.Height; var rectangleSizeWidth = textWidth < 15 ? 15 : textWidth; var rectangleSizeHeight = textHeight < 15 ? 15 : textHeight; var size = new Size(rectangleSizeWidth, rectangleSizeHeight); Rect rect = new Rect(new Point(point.X - rectangleSizeWidth / 2, point.Y - rectangleSizeHeight / 2), size); drawingContext.DrawRoundedRectangle(renderBrush, renderPen, rect, renderRadius, renderRadius); drawingContext.DrawText(formattedText, new Point(point.X - textWidth / 2, point.Y - textHeight / 2)); } 这段代码就是在目标控件的右上角绘制一个带圆角的rectangle,背景色为红色,再绘制一个文本用来显示content. 第7步,运用到项目中: <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center"> <cc:CornerButton ButtonType="OutLine" Width="200" Height="30" cc:Badge.Content="{Binding ElementName=textbox1, Path=Text, UpdateSourceTrigger=PropertyChanged}" Margin="10"/> <cc:CornerTextBox x:Name="textbox1" Width="200" Height="30" Text="12" VerticalContentAlignment="Center" WaterText="BadgeContent"/> </StackPanel> cc是表示badge所在的命名空间,然后你就会发现,你改变textbox的值的时候,badge会跟着textbox的值发生变化哦. 转自https://www.cnblogs.com/lvpp13/p/18354811 该文章在 2024/11/7 9:53:34 编辑过 |
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