WPF 调试时拖拽不生效

WPF窗体代码

<Window x:Class="SerialLabelDemo.Test.Window10"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:SerialLabelDemo.Test"
        mc:Ignorable="d" AllowDrop="True"
            Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="35"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <StackPanel Grid.Row="0" Orientation="Horizontal" Background="#CC0088FF">
            <Button
          Name="btClear" Click="ClickClear" Content="Clear" Margin="5"
        />
            <Border BorderBrush="Black" BorderThickness="1" MaxHeight="25">
                <CheckBox
            Name="cbWrap"
            Content="Wrap Content" 
            IsChecked="False" 
            Margin="5" Padding="5,0,0,0" 
            VerticalAlignment="Center" VerticalContentAlignment="Center" 
            Click="ClickWrap"
          />
            </Border>
            <Label 
          Name="lblInstructions" 
          HorizontalContentAlignment="Center" VerticalContentAlignment="Center"
          FontWeight="Bold"
          Content="     Drop a single file below to display its contents.     "
        />
        </StackPanel>

        <TextBox
        Name="tbDisplayFileContents" 
        Grid.Row="1" 
        AcceptsReturn="True" AcceptsTab="True" 
        AllowDrop="True" 
        BorderThickness="1" BorderBrush="Black" 
        HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"
        
        PreviewDragOver="EhDragOver" PreviewDrop="EhDrop"/>
        <TextBlock Text="管理员运行是不可以进行拖拽的"/>

    </Grid>
</Window>

窗体后台代码

    public partial class Window10 : Window
    {
        public Window10()
        {
            InitializeComponent();

            if ((bool)cbWrap.IsChecked)
                tbDisplayFileContents.TextWrapping = TextWrapping.Wrap;
            else
                tbDisplayFileContents.TextWrapping = TextWrapping.NoWrap;
        }

        private void ClickClear(object sender, RoutedEventArgs args)
        {
            tbDisplayFileContents.Clear();
        }

        private void ClickWrap(object sender, RoutedEventArgs args)
        {
            if ((bool)cbWrap.IsChecked)
                tbDisplayFileContents.TextWrapping = TextWrapping.Wrap;
            else
                tbDisplayFileContents.TextWrapping = TextWrapping.NoWrap;
        }

        private void EhDragOver(object sender, DragEventArgs args)
        {
            // As an arbitrary design decision, we only want to deal with a single file.
            args.Effects = IsSingleFile(args) != null ? DragDropEffects.Copy : DragDropEffects.None;

            // Mark the event as handled, so TextBox's native DragOver handler is not called.
            args.Handled = true;
        }

        private void EhDrop(object sender, DragEventArgs args)
        {
            // Mark the event as handled, so TextBox's native Drop handler is not called.
            args.Handled = true;

            var fileName = IsSingleFile(args);
            if (fileName == null) return;

            var fileToLoad = new StreamReader(fileName);
            tbDisplayFileContents.Text = fileToLoad.ReadToEnd();
            fileToLoad.Close();

            // Set the window title to the loaded file.
            Title = "File Loaded: " + fileName;
        }

        // If the data object in args is a single file, this method will return the filename.
        // Otherwise, it returns null.
        private string IsSingleFile(DragEventArgs args)
        {
            // Check for files in the hovering data object.
            if (args.Data.GetDataPresent(DataFormats.FileDrop, true))
            {
                var fileNames = args.Data.GetData(DataFormats.FileDrop, true) as string[];
                // Check fo a single file or folder.
                if (fileNames.Length == 1)
                {
                    // Check for a file (a directory will return false).
                    if (File.Exists(fileNames[0]))
                    {
                        // At this point we know there is a single file.
                        return fileNames[0];
                    }
                }
            }
            return null;
        }
    }

　　运行画面：

 

 调试时发现无法拖拽：

原因，以管理员启动VS进行调试是不能拖拽外部文件到程序中的

在debug目录下以管理员运行exe运行也是一样的结果

说是UAC检测的系统上管理员权限开启的程序时无法支持外部拖拽的

 

同行描述原因见https://www.cnblogs.com/swack/p/10508649.html