Question

我会尝试一点Shapemoving并编写以下应用程序：

<Window x:Class="WpfApplication7.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
  <Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="27" />
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <ToolBar Grid.Row="0"/>
    <Canvas Grid.Row="1" MouseDown="OnMouseDown" MouseUp="OnMouseUp" MouseMove="OnMouseMove">
        <Ellipse Width="100" Height="100" Fill="Red" Canvas.Left="50" Canvas.Top="50" />
        <Ellipse Width="100" Height="100" Fill="Red" Canvas.Left="180" Canvas.Top="50" />
        <Rectangle Width="100" Height="100" Fill="Blue" Canvas.Left="220" Canvas.Top="160" />
    </Canvas>
  </Grid>
</Window>

和守则背后：

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace WpfApplication7
{
  public partial class MainWindow
  {
    private UIElement SelectedObject { get; set; }
    private bool captureMouse;
    private Point diffPosition;

    public MainWindow()
    {
        InitializeComponent();
    }

    private void OnMouseDown(object sender, MouseButtonEventArgs e)
    {
        SelectedObject = e.Source as UIElement;
        if (SelectedObject != null)
        {
            captureMouse = SelectedObject.CaptureMouse();
            diffPosition = e.GetPosition(SelectedObject);
        }
    }

    private void OnMouseUp(object sender, MouseButtonEventArgs e)
    {
        if (captureMouse)
        {
            SelectedObject.ReleaseMouseCapture();
        }
        SelectedObject = null;
    }

    private void OnMouseMove(object sender, MouseEventArgs e)
    {
        if (SelectedObject != null)
        {
            Canvas.SetLeft(SelectedObject, e.GetPosition(this).X - diffPosition.X);
            Canvas.SetTop(SelectedObject, e.GetPosition(this).Y - diffPosition.Y);
        }
    }
  }
}

我认为diffPosition中的点击点OnMouseDown与GetPosition SelectedObject相对于{{1}}保存了几行代码，但工具栏的高度被添加。所以我的Y坐标比我预期的多27个像素。如果我删除工具栏，一切正常。我需要做什么才能通过表单中的工具栏获得正确的偏移量？

我知道这只是一个小错误，但我找不到它。

Answer 1

命名您的绘图区域：

 <Canvas Grid.Row="1" x:Name="drawingArea" ...>
    ...
 </Canvas>

并与drawingArea的比较位置。

e.GetPosition(this.drawingArea)

这样您就不必担心布局更改等。

MouseEventArgs.GetPosition在WPF中无法正常工作

1 个答案: