在WPF中如何做到，点击按钮，弹出一个带箭头的消息框，箭头对准按钮，效果如图所示。
XAML代码
<Button Grid.Row="1" Grid.Column="1" x:Name="button" Content="..." HorizontalAlignment="Right" Margin="0,0,100,0" VerticalAlignment="Top"/> <Popup x:Name="Popup1" IsOpen="False" StaysOpen="True" PlacementTarget="{Binding ElementName=button}" AllowsTransparency="True" Placement="Center" HorizontalOffset="0" VerticalOffset="36"> <Grid Background="Transparent" > <Grid.RowDefinitions> <RowDefinition></RowDefinition> <RowDefinition></RowDefinition> </Grid.RowDefinitions> <Border Grid.Row="0" Background="Transparent"> <Canvas Background="Transparent"> <TextBlock x:Name="TextBlock1" Background="Transparent" Canvas.Left="0" Canvas.Top="0" Padding="0 1.1 0 0" FontSize="20" Foreground="Blue">^</TextBlock> </Canvas> </Border> <Border Grid.Row="1" Background="BurlyWood" BorderThickness="1" BorderBrush="#ccc"> <TextBlock>123456789abcdefghijklmnopqrstuvw</TextBlock> </Border> </Grid> </Popup>
CS代码
public MainWindow() { InitializeComponent(); Popup1.Opened += Popup1_Opened; Popup1.Closed += Popup1_Closed; } private void Popup1_Closed(object sender, EventArgs e) { TextBlock1.SetValue(Canvas.LeftProperty, (double)0); } private void Popup1_Opened(object sender, EventArgs e) { Point point = button.TranslatePoint(new Point(0, 0), this); Point point2 = TextBlock1.TranslatePoint(new Point(0, 0), this); TextBlock1.SetValue(Canvas.LeftProperty, point.X - point2.X); } private void button_Click(object sender, RoutedEventArgs e) { Popup1.IsOpen = true; }
看代码其实很简单，只是没想到办法，突然想到了就写一个简单的例子做演示。
WPF Popup弹出框箭头自动定位效果
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原文地址：https://www.cnblogs.com/chengNet/p/11632675.html