asp.net中Wpf拖拽滑动效果示例

作者：袖梨 2022-06-25

wpf其实支持拖拽是很简单的。使用drag事件或者自定义鼠标事件都是可以实现的。

今天分享一个用鼠标的点击和up事件实现的拖拽滑动效果。

IT分享wpf教程-Wpf拖拽滑动效果

首先在xaml中定义一个ScrollViewer。

代码如下 复制代码
xmlns="http://schemas.*mi*croso*ft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.**microso*ft.com/winfx/2006/xaml"
Title="MainWindow" Height="400" Width="680">

后台模拟一下按钮数据：

代码如下 复制代码
///
/// 创建按钮集合
///
///
public void CreateNgEtry(ref Grid grid)
{
grid.Children.Clear();
grid.RowDefinitions.Clear();
grid.ColumnDefinitions.Clear();
for (int i = 0; i {
}
for (int i = 0; i {
grid.RowDefinitions.Add(new RowDefinition());
}
for (int i = 0; i {
grid.ColumnDefinitions.Add(new ColumnDefinition());
for (int j = 0; j {
Button but = new Button();
but.Height = 80;
but.Width = 110;
but.FontSize = 16;
grid.Children.Add(but);
System.Windows.Controls.Grid.SetColumn(but, j);
System.Windows.Controls.Grid.SetRow(but, i);
but.Content = "Test" + i.ToString();
}
}
}

鼠标按下时的事件处理，记住当前的位置：

代码如下 复制代码
private void canvas_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
targetElement = Mouse.DirectlyOver as UIElement;
if (targetElement != null)
{
targetPoint = e.GetPosition(NGEntry);
}
}

当鼠标拖动时：

代码如下 复制代码

private void canvas_PreviewMouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed && targetElement != null)
{
var pCanvas = e.GetPosition(canvas);
double gridtop = Convert.ToDouble(NGEntry.GetValue(Canvas.TopProperty));
NGEntry.SetValue(Canvas.TopProperty, pCanvas.Y - targetPoint.Y);

}
}

当鼠标放下事件：

代码如下 复制代码

private void canvas_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
double gridtop = Convert.ToDouble(NGEntry.GetValue(Canvas.TopProperty));
double gridh = NGEntry.ActualHeight;
double viewh = canvas.ActualHeight;
if (gridtop > 0)
{
NGEntry.SetValue(Canvas.TopProperty, 0d);
}
if (viewh + (Math.Abs(gridtop)) > gridh)
{
NGEntry.SetValue(Canvas.TopProperty, viewh - gridh);
}
}

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