【发布时间】：2017-10-20 23:50:58
【问题描述】：
我得到了以下 WPF 表单。我是 WPF 的新手 .. 即使调整大小，我如何将椭圆保持在中心？我包含了调整大小时缩放的代码
<Window x:Name="mainWindow" x:Class="SpectrumVisualizer.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="369.737" Width="567.487" Loaded="Window_Loaded" SizeChanged="mainWindow_SizeChanged">
<DockPanel>
<Canvas x:Name="MyCanvas" Margin="0,-41,-14,0" DockPanel.Dock="Left">
<Viewbox Stretch="Uniform" Height="380">
<Grid Name="MainGrid" Background="Black" Height="339" Width="499" Canvas.Top="41">
<Grid.ColumnDefinitions>
</Grid.ColumnDefinitions>
<Ellipse x:Name="Bar01" Fill="Red" HorizontalAlignment="Left" Height="300" Stroke="Black" VerticalAlignment="Top" Width="467" Margin="19,32,0,0"/>
<Ellipse x:Name="Bar02" Fill="Orange" HorizontalAlignment="Left" Margin="105,32,0,0" Stroke="Black" Width="295" VerticalAlignment="Top" Height="300"/>
<Ellipse x:Name="Bar03" Fill="Yellow" HorizontalAlignment="Left" Height="141" Margin="19,107,0,0" Stroke="Black" VerticalAlignment="Top" Width="467"/>
<Ellipse x:Name="Bar04" Fill="LimeGreen" HorizontalAlignment="Left" Height="232" Margin="138,64,0,0" Stroke="Black" VerticalAlignment="Top" Width="231"/>
<Ellipse x:Name="Bar05" Fill="Green" HorizontalAlignment="Left" Height="280" Margin="194,42,0,0" Stroke="Black" VerticalAlignment="Top" Width="120"/>
<Ellipse x:Name="Bar06" Fill="Turquoise" HorizontalAlignment="Left" Height="106" Margin="67,125,0,0" Stroke="Black" VerticalAlignment="Top" Width="363"/>
<Ellipse x:Name="Bar07" Fill="Cyan" HorizontalAlignment="Left" Height="183" Margin="167,88,0,0" Stroke="Black" VerticalAlignment="Top" Width="174"/>
<Ellipse x:Name="Bar08" Fill="Blue" HorizontalAlignment="Left" Height="232" Margin="204,64,0,0" Stroke="Black" VerticalAlignment="Top" Width="100"/>
<Ellipse x:Name="Bar09" Fill="Violet" HorizontalAlignment="Left" Height="75" Margin="105,139,0,0" Stroke="Black" VerticalAlignment="Top" Width="295"/>
<Ellipse x:Name="Bar10" Fill="Magenta" HorizontalAlignment="Left" Height="129" Margin="194,119,0,0" Stroke="Black" VerticalAlignment="Top" Width="120"/>
</Grid>
</Viewbox>
</Canvas>
</DockPanel>
</Window>
后面的代码：
private void mainWindow_SizeChanged(object sender, SizeChangedEventArgs e)
{
MyCanvas.Width = e.NewSize.Width;
MyCanvas.Height = e.NewSize.Height;
double xChange = 1, yChange = 1;
if (e.PreviousSize.Width != 0)
xChange = (e.NewSize.Width / e.PreviousSize.Width);
if (e.PreviousSize.Height != 0)
yChange = (e.NewSize.Height / e.PreviousSize.Height);
ScaleTransform scale = new ScaleTransform(MyCanvas.LayoutTransform.Value.M11 * xChange, MyCanvas.LayoutTransform.Value.M22 * yChange);
MyCanvas.LayoutTransform = scale;
MyCanvas.UpdateLayout();
}
【问题讨论】：