Silverlight 4: How to Drag and Drop External Files?

Now if your dev environment is ready then we can go further to implement the same. Excited so much to do it? Create a Silverlight project which will create “MainPage.xaml” for you. Inside the MainPage.xaml add a ScrollViewer containing a WrapPanel. Your ScrollViewer will have a fixed Height & Width where as your WrapPanel will be free size. This ensures that, if more components are added inside the WrapPanel it will automatically add a scrollbar to it. So, you can scroll through the child components. In this example I want to drop some external image files inside this panel. So, I will set the WrapPanel “AllowDrop” property to true. This will make the panel droppable.

On the Drop event handler of the wrap panel you will get the dropped files as data to the DropEventArgs which has an array of FileInfo. DataFormats.FileDrop sets the droppable permission to the panel.

FileInfo[] droppedFiles = e.Data.GetData(DataFormats.FileDrop) as FileInfo[];

void imageContainer_Drop(object sender, DragEventArgs e)
{
    FileInfo[] droppedFiles = e.Data.GetData(DataFormats.FileDrop) as FileInfo[];

    foreach (FileInfo droppedFile in droppedFiles)
    {
        if (IsSupportedImageFile(droppedFile.Extension))
        {
            Border imagePlaceHolder = new Border()
            {
                Child = CreateImage(droppedFile),
                Background = transparentColor,
                Margin = new Thickness(10.0),
                Cursor = Cursors.Hand,
            }; 
            
            ToolTipService.SetToolTip(imagePlaceHolder, droppedFile.Name);

            imagePlaceHolder.MouseEnter += imagePlaceHolder_MouseEnter;
            imagePlaceHolder.MouseLeave += imagePlaceHolder_MouseLeave;

            imageContainer.Children.Add(imagePlaceHolder);
        }
    }
}

private Image CreateImage(FileInfo droppedFile)
{
    using (FileStream fileStream = droppedFile.OpenRead())
    {
        BitmapImage bitmapImage = new BitmapImage();
        bitmapImage.SetSource(fileStream);

        return new Image() { Source = bitmapImage, Width = 100, Margin = new Thickness(5.0) };
    }
}