实现拖动文件到窗体（控件）

时间：2015-05-21 17:03:23 阅读：167 评论：0 收藏：0 [点我收藏+]

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前言

实现从窗口外部拖文件到窗口内部并自动捕获文件地址。

第一步开启属性

启用底层Window的AllowDrop属性，添加Drop事件。

Drop事件：当你拖动文件到对应控件后，松开触发。

除Drop事件外，我们还可以使用DragEnter、DragOver、DragLeave三个事件。

第二步事件代码

private void MainWindow_Drop(object sender, DragEventArgs e)
{
    string msg = "Drop";
    if (e.Data.GetDataPresent(DataFormats.FileDrop))
    {
        msg = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
    }

    MessageBox.Show(msg);
}

实例1：

在WPF中的实现和WinForm中的实现99%相似，将要实现接受拖拽释放的控件添加DragEnter事件和Drop事件，本例中控件Grid grid作为接受控件，添加事件操作如下：

private void grid_Drop(object sender, DragEventArgs e)
{
    string fileName = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
    //获得文件名后的操作...
}

private void grid_DragEnter(object sender, DragEventArgs e)
{
    if (e.Data.GetDataPresent(DataFormats.FileDrop))
        e.Effects = DragDropEffects.Link;                            //WinForm中为e.Effect = DragDropEffects.Link
    else e.Effects = DragDropEffects.None;                      //WinFrom中为e.Effect = DragDropEffects.None
}

实例2：

<Window x:Class="GetPixelFormat.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="获取图片的像素格式" Height="450" Width="565">
    <Grid  DragEnter="Grid_DragEnter" Drop="Grid_Drop"  Background="White"
          >
        <Label Content="获取图片的PixelFormat（1.0支持单个文件拖入）" 
               HorizontalAlignment="Left" 
               Margin="155,19,0,0" VerticalAlignment="Top"/>
        <Label Content="文件名：" HorizontalAlignment="Left" Margin="109,68,0,0" VerticalAlignment="Top"/>
        <Label Name="lblFileName"  Content="Label" HorizontalAlignment="Left" Margin="173,68,0,0" VerticalAlignment="Top" FontFamily="Microsoft YaHei"/>
        <Label Content="PixelFormat:" HorizontalAlignment="Left" Margin="87,129,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.697,0.627"/>
        <Label Name="lblPixedFormat" Content="Label" HorizontalAlignment="Left" Margin="173,129,0,0" VerticalAlignment="Top" FontFamily="Microsoft YaHei"/>
        <Label Content="图片对象：" HorizontalAlignment="Left" Margin="97,200,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.016,-0.604"/>
        <Border BorderBrush="#FFD4FBFD" 
                BorderThickness="1" 
                HorizontalAlignment="Left"
                Margin="181,200,0,0" 
                VerticalAlignment="Top"
                >
            <Image Name="imgOne"
               HorizontalAlignment="Left" 
               VerticalAlignment="Top"  />
        </Border>
    </Grid>
</Window>

    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            //启用接收 拖放
            this.AllowDrop = true;
        }

        private void Grid_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
                e.Effects = DragDropEffects.Link;
            else
            {
                e.Effects = DragDropEffects.None;
                lblFileName.Foreground = System.Windows.Media.Brushes.Red;
                lblFileName.Content = "拖入的内容不是文件";
            }
        }

        private void Grid_Drop(object sender, DragEventArgs e)
        {
            System.Array array = e.Data.GetData(DataFormats.FileDrop) as Array;
            string fileName = array.GetValue(0).ToString();
            lblFileName.Content = fileName;
            //获取图片
            System.Drawing.Bitmap bit = new Bitmap(fileName);

            //获取图片的格式
            lblPixedFormat.Content = bit.PixelFormat;

            //显示图片
            IntPtr hBitmap = bit.GetHbitmap();
            ImageSource imgS = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                hBitmap,
                IntPtr.Zero,
                Int32Rect.Empty,
                BitmapSizeOptions.FromEmptyOptions()
                );

            imgOne.Source = imgS;
        }
    }