[英]Drag And Drop Not Working In ScrollViewer
My problem is the drag and drop of border become not workin when I wrap the canvas inside the scrollviewer. 我的问题是,当我将画布包裹在scrollviewer中时,边框的拖放变得不起作用。
1200x1200 canvas put in the 500x500 scrollviewer. 将1200x1200画布放入500x500滚动查看器中。 I want the canvas is scrollable (touch slide) in the scrollviewer. 我希望画布在scrollviewer中可滚动(触摸幻灯片)。 The drag and drop in canvas is working perfectly before I insert in the scrollviewer. 在画布上进行拖放操作之前,我可以将其完美地插入到滚动查看器中。
MainWindow.xaml MainWindow.xaml
<Grid ClipToBounds="True">
<ScrollViewer Name="scbb" Width="500" Height="500" HorizontalScrollBarVisibility="Hidden"
VerticalScrollBarVisibility="Hidden" HorizontalAlignment="Left"
VerticalAlignment="Top" Background="LightBlue" ScrollViewer.CanContentScroll="True">
<Canvas x:Name="canvas" Width="1200" Height="1200"
MouseLeftButtonDown="CanvasMouseLeftButtonDown"
MouseLeftButtonUp="CanvasMouseLeftButtonUp"
MouseMove="CanvasMouseMove">
</Canvas>
</ScrollViewer>
<Button x:Name="btnEnable" Content="Enable" Height="50" Width="50" Margin="0,0,115,10" VerticalAlignment="Bottom"
HorizontalAlignment="Right" Click="btnEnable_Click"/>
<Button Content="Add Image" Width="100" Height="100" VerticalAlignment="Bottom"
HorizontalAlignment="Right" Click="AddButtonClick" Margin="0,0,10,10"/>
</Grid>
MainWindow.xaml.cs MainWindow.xaml.cs
private void AddButtonClick(object sender, RoutedEventArgs e)
{
int iNum = SETTING.GetTableRunningNumber();
var borderWrap = new Border();
borderWrap.Width = 100;
borderWrap.Height = 100;
borderWrap.Background = Brushes.Green;
var label1 = new Label();
label1.VerticalAlignment = VerticalAlignment.Center;
label1.HorizontalAlignment = HorizontalAlignment.Center;
label1.Content = "Table " + iNum.ToString();
label1.Name = "Table" + iNum.ToString();
label1.Foreground = Brushes.White;
label1.FontWeight = FontWeights.Bold;
borderWrap.Child = label1;
borderWrap.MouseDown += TableMouseDown;
Canvas.SetLeft(borderWrap, 10);
Canvas.SetTop(borderWrap, 10);
canvas.Children.Add(borderWrap);
iNum += 1;
SETTING.SetTableRunningNumber(iNum);
}
private Point mousePosition;
private Border draggedBorder;
private void TableMouseDown(object sender, MouseButtonEventArgs e)
{
if (!SETTING.GetEnableDrag())
{
var cLabel = e.Source as Label;
var bBorder = e.Source as Border;
if (cLabel != null)
{
MessageBox.Show(cLabel.Name.ToString());
}
}
}
private void CanvasMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (SETTING.GetEnableDrag())
{
var dBorder = e.Source as Border;
var cLabel = e.Source as Label;
if (dBorder == null)
{
dBorder = (Border)cLabel.Parent;
}
if (dBorder != null && canvas.CaptureMouse())
{
mousePosition = e.GetPosition(canvas);
draggedBorder = dBorder;
Panel.SetZIndex(draggedBorder, 1);
}
}
}
async Task PutTaskDelay100()
{
await Task.Delay(100);
}
private async void CanvasMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
if (SETTING.GetEnableDrag())
{
await PutTaskDelay100();
if (draggedBorder != null)
{
canvas.ReleaseMouseCapture();
Panel.SetZIndex(draggedBorder, 0);
draggedBorder = null;
}
}
}
private void CanvasMouseMove(object sender, MouseEventArgs e)
{
if (SETTING.GetEnableDrag())
{
double canvasSize = 1200;
if (draggedBorder != null)
{
var position = e.GetPosition(canvas);
var offset = position - mousePosition;
mousePosition = position;
double newTop = Canvas.GetTop(draggedBorder) + offset.Y;
double newLeft = Canvas.GetLeft(draggedBorder) + offset.X;
if (newTop < 0)
{
newTop = 0;
}
else if (newTop + draggedBorder.ActualWidth > canvasSize)
newTop = canvasSize - draggedBorder.ActualWidth;
if (newLeft < 0)
{
newLeft = 0;
}
else if (newLeft + draggedBorder.ActualWidth > canvasSize)
newLeft = canvasSize - draggedBorder.ActualWidth;
Canvas.SetLeft(draggedBorder, newLeft);
Canvas.SetTop(draggedBorder, newTop);
}
}
}
I had the problem months ago and solved it in the code behind with these additions. 几个月前我遇到了问题,并通过这些附加功能在后面的代码中解决了该问题。
After the InitializeComponent in the WindowMain.xaml.cs add: 在WindowMain.xaml.cs中的InitializeComponent之后添加:
public WindowMain()
{
InitializeComponent();
// your code, etc.
scrollViewer.AllowDrop = true;
scrollViewer.PreviewDragEnter += scrollViewer_PreviewDragEnter;
scrollViewer.PreviewDragOver += scrollViewer_PreviewDragOver;
scrollViewer.Drop += scrollViewer_Drop;
}
void scrollViewer_PreviewDragEnter(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent(DataFormats.FileDrop))
{
e.Effects = DragDropEffects.Copy;
}
else
{
e.Effects = DragDropEffects.None;
}
}
void scrollViewer_PreviewDragOver(object sender, DragEventArgs e)
{
e.Handled = true;
}
bool IsDataAvailable = false;
void scrollViewer_Drop(object sender, DragEventArgs e)
{
// Get data object
var dataObject = e.Data as DataObject;
// Check for file list
if (dataObject.ContainsFileDropList())
{
// Process file names
StringCollection fileNames = dataObject.GetFileDropList();
bool isIsDataAvailable = false;
try
{
var uri = new Uri(fileNames[0]);
BitmapSource imageSource = new BitmapImage(uri);
isIsDataAvailable = true;
}
catch (Exception error)
{
string errorMessage = error.ToString();
}
finally
{
IsDataAvailable = isIsDataAvailable;
}
}
}
My program just loads a dropped file from the explorer file list I drop on the ScrollViewer . 我的程序只是从放置在ScrollViewer上的资源管理器文件列表中加载了放置的文件。 The scbb.AllowDrop=true
in the ScrollViewer has to be set. scbb.AllowDrop=true
在ScrollViewer中设置scbb.AllowDrop=true
。 And the routines to handle basic drag and drop. 以及处理基本拖放的例程。 Your code should work once the ScrollViewer allows dropping. 一旦ScrollViewer允许删除,您的代码就应该可以工作。
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