WPF DATAGRID 实现拖拽换行

WPF DataGrid可以通过实现拖拽换行来改变数据行的顺序。以下是实现方法：

1. 首先，在DataGrid的XAML中添加以下属性：AllowDrop="True"和PreviewMouseLeftButtonDown="DataGrid_PreviewMouseLeftButtonDown"。

2. 在DataGrid的代码中添加以下事件处理程序：

private void DataGrid_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    var source = e.OriginalSource as DependencyObject;
    var row = FindVisualParent<DataGridRow>(source);
    if (row != null)
    {
        DragDrop.DoDragDrop(row, row.DataContext, DragDropEffects.Move);
        e.Handled = true;
    }
}

private void DataGrid_Drop(object sender, DragEventArgs e)
{
    var target = e.OriginalSource as DependencyObject;
    var row = FindVisualParent<DataGridRow>(target);
    if (row != null)
    {
        var data = e.Data.GetData(typeof(object));
        var sourceIndex = DataGrid.Items.IndexOf(data);
        var targetIndex = DataGrid.Items.IndexOf(row.DataContext);
        if (sourceIndex != targetIndex)
        {
            var temp = DataGrid.Items[sourceIndex];
            DataGrid.Items.RemoveAt(sourceIndex);
            DataGrid.Items.Insert(targetIndex, temp);
        }
    }
}

private static T FindVisualParent<T>(DependencyObject child) where T : DependencyObject
{
    var parent = VisualTreeHelper.GetParent(child);
    if (parent == null) return null;
    var parentT = parent as T;
    return parentT ?? FindVisualParent<T>(parent);
}

3. 在DataGrid的XAML中添加Drop事件处理程序：Drop="DataGrid_Drop"。

实现了以上步骤后，就可以通过拖拽来改变数据行的顺序了。