我需要实现this functionality in wpf.
当您转到该链接时，请注意如何拖动对象并将其放置在其他位置。我想知道是否可以使用wpf创建此文件。我已经知道如何拖动对象。有一个很好的answer in here that explains on how to do it。我需要将对象对齐。使用最后一个链接将仅使我能够拖动对象，但是在完成拖动之后，我需要它们对齐。
最佳答案
有很多不同的方法可以做到这一点，但是这里有一些想法：
一个具有XOffset，YOffset和IsSnapped附加属性的自定义面板（默认为true）。用户拖动项目时，将IsSnapped设置为false并在拖动时更新XOffset / YOffset。面板的布局逻辑可以排列高度对齐的项目（基于它们的XOffset / YOffset），除非IsSnapped为false，在这种情况下，它们只会出现在（XOffset，YOffset）处。
使用现有的拖动行为（例如由blend提供的行为），但是在放置子项时将自己的坐标强加到子项上。更新：这将不起作用，或者会很混乱，因为Blend会动态修改拖动元素的RenderTransform，而不是更新一些附加属性，您可以以此为基础进行计算。
在使用MVVM的视图模型中主要执行此操作。也就是说，在视图模型上具有“顶部”，“左侧”，“宽度”和“高度”的属性，所有属性都通过行为（DragBehavior和SizeObserver行为）进行更新。让父视图模型公开子视图模型（每个子视图代表一个可拖动项）。让父VM监视子坐标的更改并根据需要强加。
目前，我正在做类似的事情，并且与＃3在一起。尚无后悔，它比您要在此处实现的目标要复杂得多，因此您不应有任何障碍。
更新：这是我的DragDrop行为：
using System.Diagnostics;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using Kent.Boogaart.HelperTrinity.Extensions;
public static class DragDrop
{
public static readonly RoutedEvent PreviewBeginDragEvent = EventManager.RegisterRoutedEvent(
"PreviewBeginDrag",
RoutingStrategy.Tunnel,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly RoutedEvent BeginDragEvent = EventManager.RegisterRoutedEvent(
"BeginDrag",
RoutingStrategy.Bubble,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly RoutedEvent PreviewDragEvent = EventManager.RegisterRoutedEvent(
"PreviewDrag",
RoutingStrategy.Tunnel,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly RoutedEvent DragEvent = EventManager.RegisterRoutedEvent(
"Drag",
RoutingStrategy.Bubble,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly RoutedEvent PreviewEndDragEvent = EventManager.RegisterRoutedEvent(
"PreviewEndDrag",
RoutingStrategy.Tunnel,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly RoutedEvent EndDragEvent = EventManager.RegisterRoutedEvent(
"EndDrag",
RoutingStrategy.Bubble,
typeof(RoutedEventHandler),
typeof(DragDrop));
public static readonly DependencyProperty CanDragProperty = DependencyProperty.RegisterAttached(
"CanDrag",
typeof(bool),
typeof(DragDrop),
new FrameworkPropertyMetadata(OnCanDragChanged));
public static readonly DependencyProperty IsDragInProgressProperty;
public static readonly DependencyProperty DragParentProperty = DependencyProperty.RegisterAttached(
"DragParent",
typeof(FrameworkElement),
typeof(DragDrop));
public static readonly DependencyProperty XOffsetProperty = DependencyProperty.RegisterAttached(
"XOffset",
typeof(double),
typeof(DragDrop));
public static readonly DependencyProperty YOffsetProperty = DependencyProperty.RegisterAttached(
"YOffset",
typeof(double),
typeof(DragDrop));
private static readonly DependencyPropertyKey isDragInProgressPropertyKey = DependencyProperty.RegisterAttachedReadOnly(
"IsDragInProgress",
typeof(bool),
typeof(DragDrop),
new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.Inherits));
private static readonly DependencyProperty DragPointProperty = DependencyProperty.RegisterAttached(
"DragPoint",
typeof(Point?),
typeof(DragDrop),
new PropertyMetadata());
static DragDrop()
{
IsDragInProgressProperty = isDragInProgressPropertyKey.DependencyProperty;
}
public static void AddPreviewBeginDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(PreviewBeginDragEvent, handler);
}
}
public static void RemovePreviewBeginDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(PreviewBeginDragEvent, handler);
}
}
public static void AddBeginDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(BeginDragEvent, handler);
}
}
public static void RemoveBeginDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(BeginDragEvent, handler);
}
}
public static void AddPreviewDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(PreviewDragEvent, handler);
}
}
public static void RemovePreviewDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(PreviewDragEvent, handler);
}
}
public static void AddDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(DragEvent, handler);
}
}
public static void RemoveDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(DragEvent, handler);
}
}
public static void AddPreviewEndDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(PreviewEndDragEvent, handler);
}
}
public static void RemovePreviewEndDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(PreviewEndDragEvent, handler);
}
}
public static void AddEndDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.AddHandler(EndDragEvent, handler);
}
}
public static void RemoveEndDragHandler(DependencyObject dependencyObject, RoutedEventHandler handler)
{
var inputElement = dependencyObject as IInputElement;
if (inputElement != null)
{
inputElement.RemoveHandler(EndDragEvent, handler);
}
}
public static bool GetCanDrag(FrameworkElement frameworkElement)
{
frameworkElement.AssertNotNull("frameworkElement");
return (bool)frameworkElement.GetValue(CanDragProperty);
}
public static void SetCanDrag(FrameworkElement frameworkElement, bool canDrag)
{
frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(CanDragProperty, canDrag);
}
public static FrameworkElement GetDragParent(DependencyObject dependencyObject)
{
dependencyObject.AssertNotNull("dependencyObject");
return dependencyObject.GetValue(DragParentProperty) as FrameworkElement;
}
public static void SetDragParent(DependencyObject dependencyObject, FrameworkElement dragParent)
{
dependencyObject.AssertNotNull("dependencyObject");
dependencyObject.SetValue(DragParentProperty, dragParent);
}
public static double GetXOffset(FrameworkElement frameworkElement)
{
frameworkElement.AssertNotNull("frameworkElement");
return (double)frameworkElement.GetValue(XOffsetProperty);
}
public static void SetXOffset(FrameworkElement frameworkElement, double xOffset)
{
frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(XOffsetProperty, xOffset);
}
public static double GetYOffset(FrameworkElement frameworkElement)
{
frameworkElement.AssertNotNull("frameworkElement");
return (double)frameworkElement.GetValue(YOffsetProperty);
}
public static void SetYOffset(FrameworkElement frameworkElement, double yOffset)
{
frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(YOffsetProperty, yOffset);
}
public static bool GetIsDragInProgress(DependencyObject dependencyObject)
{
dependencyObject.AssertNotNull("dependencyObject");
return (bool)dependencyObject.GetValue(IsDragInProgressProperty);
}
private static void SetIsDragInProgress(DependencyObject dependencyObject, bool isDragInProgress)
{
dependencyObject.AssertNotNull("dependencyObject");
dependencyObject.SetValue(isDragInProgressPropertyKey, isDragInProgress);
}
private static Point? GetDragPoint(FrameworkElement frameworkElement)
{
frameworkElement.AssertNotNull("frameworkElement");
return (Point?)frameworkElement.GetValue(DragPointProperty);
}
private static void SetDragPoint(FrameworkElement frameworkElement, Point? dragPoint)
{
frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(DragPointProperty, dragPoint);
}
private static void OnCanDragChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = (FrameworkElement)dependencyObject;
if ((bool)e.NewValue)
{
frameworkElement.MouseLeftButtonDown += OnFrameworkElementMouseLeftButtonDown;
frameworkElement.MouseMove += OnFrameworkElementMouseMove;
frameworkElement.MouseLeftButtonUp += OnFrameworkElementMouseLeftButtonUp;
var parent = GetDragParent<FrameworkElement>(frameworkElement);
if (parent == null)
{
frameworkElement.SetCurrentValue(XOffsetProperty, 0d);
frameworkElement.SetCurrentValue(YOffsetProperty, 0d);
}
else
{
var pointRelativeToParent = frameworkElement.TranslatePoint(new Point(0, 0), parent);
frameworkElement.SetCurrentValue(XOffsetProperty, pointRelativeToParent.X);
frameworkElement.SetCurrentValue(YOffsetProperty, pointRelativeToParent.Y);
}
}
else
{
frameworkElement.MouseLeftButtonDown -= OnFrameworkElementMouseLeftButtonDown;
frameworkElement.MouseMove -= OnFrameworkElementMouseMove;
frameworkElement.MouseLeftButtonUp -= OnFrameworkElementMouseLeftButtonUp;
}
}
private static void OnFrameworkElementMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var frameworkElement = (FrameworkElement)sender;
var parent = GetDragParent<FrameworkElement>(frameworkElement);
if (parent == null)
{
return;
}
var previewBeginDragEventArgs = new RoutedEventArgs(PreviewBeginDragEvent);
frameworkElement.RaiseEvent(previewBeginDragEventArgs);
if (previewBeginDragEventArgs.Handled)
{
return;
}
SetIsDragInProgress(frameworkElement, true);
SetDragPoint(frameworkElement, e.GetPosition(parent));
frameworkElement.CaptureMouse();
frameworkElement.RaiseEvent(new RoutedEventArgs(BeginDragEvent));
}
private static void OnFrameworkElementMouseMove(object sender, MouseEventArgs e)
{
var frameworkElement = (FrameworkElement)sender;
if (frameworkElement.IsMouseCaptured)
{
var previewDragEventArgs = new RoutedEventArgs(PreviewDragEvent);
frameworkElement.RaiseEvent(previewDragEventArgs);
if (previewDragEventArgs.Handled)
{
return;
}
var parent = GetDragParent<FrameworkElement>(frameworkElement);
if (parent == null)
{
return;
}
var currentPointRelativeToParent = e.GetPosition(parent);
var dragPoint = GetDragPoint(frameworkElement);
Debug.Assert(dragPoint.HasValue, "dragPoint should be set.");
frameworkElement.SetCurrentValue(XOffsetProperty, GetXOffset(frameworkElement) + (currentPointRelativeToParent.X - dragPoint.Value.X));
frameworkElement.SetCurrentValue(YOffsetProperty, GetYOffset(frameworkElement) + (currentPointRelativeToParent.Y - dragPoint.Value.Y));
SetDragPoint(frameworkElement, currentPointRelativeToParent);
frameworkElement.RaiseEvent(new RoutedEventArgs(DragEvent));
}
}
private static void OnFrameworkElementMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
var frameworkElement = (FrameworkElement)sender;
if (frameworkElement.IsMouseCaptured)
{
frameworkElement.RaiseEvent(new RoutedEventArgs(PreviewEndDragEvent));
SetDragPoint(frameworkElement, null);
frameworkElement.ReleaseMouseCapture();
frameworkElement.RaiseEvent(new RoutedEventArgs(EndDragEvent));
SetIsDragInProgress(frameworkElement, false);
}
}
private static T GetDragParent<T>(DependencyObject dependencyObject)
where T : DependencyObject
{
var dragParent = GetDragParent(dependencyObject) as T;
if (dragParent != null)
{
return dragParent;
}
var parent = VisualTreeHelper.GetParent(dependencyObject);
while (parent != null && !(parent is T))
{
parent = VisualTreeHelper.GetParent(parent);
}
return (T)parent;
}
}