【发布时间】：2020-01-04 04:15:28
【问题描述】：
我在堆栈面板中有一个矩形形状，我想使用 WPF 用鼠标在网格中拖放！ 如果有人可以帮助我，我将不胜感激？ 谢谢大家。
【问题讨论】：
-
您是否尝试过任何方法并且有一些代码可以分享但有问题或者您不知道从哪里开始？如果是后者：msdn.microsoft.com/en-us/library/ms742859.aspx
【发布时间】：2020-01-04 04:15:28
【问题描述】：
下面是一个非常简单的实现。它只是处理Rectangle 的鼠标按钮向下/向上/移动事件，以便将其与鼠标移动一起定位。没有错误检查，也没有任何东西可以阻止用户将矩形拖离 Canvas 并将其留在那里。
XAML：
<Window x:Class="WpfApplication6.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>
<Canvas Name="canvas">
<Rectangle
Name="rect"
Width="50"
Height="50"
Canvas.Left="0"
Canvas.Top="0"
Fill="Red"
MouseLeftButtonDown="rect_MouseLeftButtonDown"
MouseLeftButtonUp="rect_MouseLeftButtonUp"
MouseMove="rect_MouseMove"
/>
</Canvas>
</Grid>
</Window>
代码背后：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace WpfApplication6
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private bool _isRectDragInProg;
public MainWindow()
{
InitializeComponent();
}
private void rect_MouseLeftButtonDown( object sender, MouseButtonEventArgs e )
{
_isRectDragInProg = true;
rect.CaptureMouse();
}
private void rect_MouseLeftButtonUp( object sender, MouseButtonEventArgs e )
{
_isRectDragInProg = false;
rect.ReleaseMouseCapture();
}
private void rect_MouseMove( object sender, MouseEventArgs e )
{
if( !_isRectDragInProg ) return;
// get the position of the mouse relative to the Canvas
var mousePos = e.GetPosition(canvas);
// center the rect on the mouse
double left = mousePos.X - (rect.ActualWidth / 2);
double top = mousePos.Y - (rect.ActualHeight / 2);
Canvas.SetLeft( rect, left );
Canvas.SetTop( rect, top );
}
}
}
【讨论】：
为了在项目控件中实现拖放，其中项目由画布以外的任何东西布置，那么我强烈建议查看Bea Stollnitz solution。这是一个完全可重用的解决方案，可以使用附加属性在任何项目控件之间拖放。
更新：鉴于 Bea 的博客已消失，基于她的解决方案的其他帖子仍然可用：
【讨论】：
-
链接已损坏。还记得解决方案吗？
-
还有一些其他人参考了她的作品。 blogs.claritycon.com/blog/2009/03/…
-
参考 2 和 3 不再起作用，请更新您的帖子
扩展@Ed S 回答的内容。使用画布的问题是您基本上可以将控件拖动到边界之外。如果您想确保它不会越界，我创建了一个简单的应用程序，如果您有两个形状，您可以将它们一起移动或单独拖动。当然，我有一个名为 ChkDual 模式的复选框来决定形状是否必须一起移动。您可以根据需要编辑该功能。
<Grid>
<!--Set some height and width as you like-->
<Canvas x:Name="CnvBarCodeImage" AllowDrop="True">
</Canvas>
<Grid>
private void CreateUIShapes(int numberOfWindows)
{
//If you want multiple shapes put it inside a loop
Thumb th = null;
th = new Thumb();
th.Width = 200;
th.Height = 100;
th.Foreground = new SolidColorBrush(Windows.UI.Colors.Transparent);
th.BorderBrush = Colors.Green;
th.BorderThickness = new Thickness(3);
th.DragDelta += (sender, e) => Th_DragDelta(sender, e);
Canvas.SetLeft(th, 100);
Canvas.SetTop(th, 80);
CnvBarCodeImage.Children.Add(th);
}
private event Action<Thumb, double, double> ChangeDimensions;
private void Th_DragDelta(object sender, DragDeltaEventArgs e, List<Dimensions> limitedWindowMovements)
{
var selectedDraggableThumb = sender as Thumb;
double left = (Canvas.GetLeft(selectedDraggableThumb) >= 0) ? Canvas.GetLeft(selectedDraggableThumb) : 0;
double top = (Canvas.GetTop(selectedDraggableThumb) >= 0) ? Canvas.GetTop(selectedDraggableThumb) : 0;
if (ChkDualMode.IsChecked == true)
{
var otherDraggableThumbs = CnvBarCodeImage.Children.OfType<Thumb>().Where(x => x != selectedDraggableThumb).ToList();
var maxTopSelected = 0
var maxLeftSelected = 0;
//There may be n number of windows.
foreach (var item in otherDraggableThumbs)
{
//TOP
//Canvas.GetTop(SelectedDraggableThumb) <= 0 || Canvas.GetTop(item) <= 0 original.
if (Canvas.GetTop(selectedDraggableThumb) <= maxTopSelected || Canvas.GetTop(item) <= maxTopSelected)
{
if (e.VerticalChange <= 0)
{
ChangeDimensions -= BarCodeServiceView_ChangeDimensions;
return;
}
}
//LEFT
//Canvas.GetLeft(SelectedDraggableThumb) <= 0 || Canvas.GetLeft(item) <= 0 original.
else if (Canvas.GetLeft(selectedDraggableThumb) <= maxLeftSelected || Canvas.GetLeft(item) <= maxLeftSelected)
{
if (e.HorizontalChange <= 0)
{
ChangeDimensions -= BarCodeServiceView_ChangeDimensions;
return;
}
}
//RIGHT
else if (Canvas.GetLeft(selectedDraggableThumb) >=
CnvBarCodeImage.ActualWidth - selectedDraggableThumb.ActualWidth ||
Canvas.GetLeft(item) >= CnvBarCodeImage.ActualWidth - item.ActualWidth)
//|| Canvas.GetLeft(SelectedDraggableThumb) >= maxRightSelected
//|| Canvas.GetLeft(item) >= maxRightSelected)
{
if (e.HorizontalChange > 0)
{
ChangeDimensions -= BarCodeServiceView_ChangeDimensions;
return;
}
}
//BOTTOM
else if (Canvas.GetTop(selectedDraggableThumb) + selectedDraggableThumb.ActualHeight >= CnvBarCodeImage.ActualHeight ||
Canvas.GetTop(item) + item.ActualHeight >= CnvBarCodeImage.ActualHeight)
{
if (e.VerticalChange >= 0)
{
ChangeDimensions -= BarCodeServiceView_ChangeDimensions;
return;
}
}
if (ChangeDimensions == null)
{
ChangeDimensions += BarCodeServiceView_ChangeDimensions;
}
}
foreach (var item in otherDraggableThumbs)
{
ChangeDimensions?.Invoke(item, e.HorizontalChange, e.VerticalChange);
}
left = (Canvas.GetLeft(selectedDraggableThumb) >= CnvBarCodeImage.ActualWidth) ? CnvBarCodeImage.ActualWidth : left;
top = (Canvas.GetTop(selectedDraggableThumb) >= CnvBarCodeImage.ActualHeight) ? CnvBarCodeImage.ActualHeight : top;
Canvas.SetLeft(selectedDraggableThumb, left + e.HorizontalChange);
Canvas.SetTop(selectedDraggableThumb, top + e.VerticalChange);
}
else
{
//In single mode limit the movement as well.
int.TryParse(selectedDraggableThumb.Name, out var indexFromName);
var limitedDimensionForWindow = limitedWindowMovements[indexFromName];
var maxTop = limitedDimensionForWindow.MaxTopPossible == null ? 0 : limitedDimensionForWindow.MaxTopPossible;
var maxLeft = limitedDimensionForWindow.MaxLeftPossible == null ? 0 : limitedDimensionForWindow.MaxLeftPossible;
var maxRight = limitedDimensionForWindow.MaxRightPossible == null ? CnvBarCodeImage.ActualWidth - selectedDraggableThumb.ActualWidth : limitedDimensionForWindow.MaxRightPossible;
var maxBottom = limitedDimensionForWindow.MaxBottomPossible == null ? CnvBarCodeImage.ActualHeight - selectedDraggableThumb.ActualHeight : limitedDimensionForWindow.MaxBottomPossible;
if (Canvas.GetTop(selectedDraggableThumb) <= maxTop)
{
if (e.VerticalChange <= 0)
{
return;
}
}
else if (Canvas.GetLeft(selectedDraggableThumb) <= maxLeft)
{
if (e.HorizontalChange <= 0)
{
return;
}
}
else if (Canvas.GetLeft(selectedDraggableThumb) >= maxRight)
{
if (e.HorizontalChange >= 0)
{
return;
}
}
else if (Canvas.GetTop(selectedDraggableThumb) >= maxBottom)
{
if (e.VerticalChange >= 0)
{
return;
}
}
left = (Canvas.GetLeft(selectedDraggableThumb) >= CnvBarCodeImage.ActualWidth) ? CnvBarCodeImage.ActualWidth : left;
top = (Canvas.GetTop(selectedDraggableThumb) >= CnvBarCodeImage.ActualHeight) ? CnvBarCodeImage.ActualHeight : top;
Canvas.SetLeft(selectedDraggableThumb, left + e.HorizontalChange);
Canvas.SetTop(selectedDraggableThumb, top + e.VerticalChange);
}
}
private void BarCodeServiceView_ChangeDimensions(Thumb sender, double arg1, double arg2)
{
if (sender != null)
{
double left = (Canvas.GetLeft(sender) > 0) ? Canvas.GetLeft(sender) : 0;
double top = (Canvas.GetTop(sender) > 0) ? Canvas.GetTop(sender) : 0;
Canvas.SetLeft(sender, left + arg1);
Canvas.SetTop(sender, top + arg2);
}
}
【讨论】：