Silverlight Pronunciation Test

using System.Windows;
using System.Windows.Controls;
using System.Windows.Interactivity;
using System.Windows.Input;
using System.IO;

namespace OpenLightGroupBehaviors
{
    [System.ComponentModel.Description("Allows files to be dropped for upload")]
    public class DropFilesToUploadBehavior : Behavior<UIElement>
    {
        private double DropUIElementOpacity;

        // Properties

        #region FileDialogDialogResultProperty

        public static readonly DependencyProperty FileDialogDialogResultProperty =
            DependencyProperty.Register("FileDialogDialogResultProperty",
            typeof(FileInfo), typeof(DropFilesToUploadBehavior), null);

        public FileInfo FileDialogDialogResult
        {
            get
            {
                return (FileInfo)base.GetValue(FileDialogDialogResultProperty);
            }
            set
            {
                base.SetValue(FileDialogDialogResultProperty, value);
            }
        }
        #endregion

        #region ParentControlProperty

        public static readonly DependencyProperty ParentControlProperty =
            DependencyProperty.Register("ParentControlProperty",
            typeof(object), typeof(DropFilesToUploadBehavior), null);

        public object ParentControl
        {
            get
            {
                return (object)base.GetValue(ParentControlProperty);
            }
            set
            {
                base.SetValue(ParentControlProperty, value);
            }
        }
        #endregion

        #region SelectedFileNameProperty

        public static readonly DependencyProperty SelectedFileNameProperty =
           DependencyProperty.Register("SelectedFileName", typeof(string),
           typeof(DropFilesToUploadBehavior), null);

        public string SelectedFileName
        {
            get
            {
                return (string)base.GetValue(SelectedFileNameProperty);
            }
            set
            {
                base.SetValue(SelectedFileNameProperty, value);
            }
        }

        #endregion

        protected override void OnAttached()
        {
            base.OnAttached();

            // Save the opacity of the element
            DropUIElementOpacity = AssociatedObject.Opacity;

            // Turn on allow drop
            AssociatedObject.AllowDrop = true;

            // Attach event handlers
            AssociatedObject.DragOver += new DragEventHandler(DropUIElement_DragOver);
            AssociatedObject.DragLeave += new DragEventHandler(DropUIElement_DragLeave);
            AssociatedObject.Drop += new DragEventHandler(DropUIElement_Drop);
        }

        protected override void OnDetaching()
        {
            base.OnDetaching();

            // Attach event handlers
            AssociatedObject.DragOver -= new DragEventHandler(DropUIElement_DragOver);
            AssociatedObject.DragLeave -= new DragEventHandler(DropUIElement_DragLeave);
            AssociatedObject.Drop -= new DragEventHandler(DropUIElement_Drop);
        }

        #region DropUIElement_DragOver
        void DropUIElement_DragOver(object sender, DragEventArgs e)
        {
            // If you hover over the drop point, change it's opacity so users will 
            // have some indication that they can drop
            AssociatedObject.Opacity = (double)0.5;
        }
        #endregion

        #region DropUIElement_DragLeave
        void DropUIElement_DragLeave(object sender, DragEventArgs e)
        {
            // Return opacity to normal
            AssociatedObject.Opacity = DropUIElementOpacity;
        }
        #endregion

        #region DropUIElement_Drop
        void DropUIElement_Drop(object sender, DragEventArgs e)
        {
            // Return opacity to normal
            AssociatedObject.Opacity = DropUIElementOpacity;

            // If there is something being dropped upload it
            if (e.Data != null)
            {
                FileInfo[] Dropfiles = e.Data.GetData(DataFormats.FileDrop) as FileInfo[];

                // Set the file to the FileInfo property
                // this should be bound to the ViewModel by the designer
                FileDialogDialogResult = Dropfiles[0];

                // Check File Extension
                if (!CheckFileExtension(FileDialogDialogResult.Extension))
                {
                    // Show error
                    MessageBox.Show("Only .gif, .jpg, .jpeg, .doc, .docx, .xls, .xlsx, .pdf, .png, .txt, .wav files may be used.");
                    // Clear the selected file
                    FileDialogDialogResult = null;
                }
                else
                {
                    SelectedFileName = ShortenFileName(FileDialogDialogResult.Name);

                    // Change to selected file Visual State
                    VisualStateManager.GoToState((Control)ParentControl, "FileSelectedState", true);
                }
            }
        }
        #endregion

        #region ShortenFileName
        private string ShortenFileName(string filename)
        {
            string strFilename = "...";

            if (filename.Length > 10)
            {
                strFilename = filename.Substring(0, 10) + " ...";
            }
            else
            {
                strFilename = filename;
            }

            return strFilename;
        }
        #endregion

        #region CheckFileExtension
        private bool CheckFileExtension(string strExtension)
        {
            if (
                string.Compare(Path.GetExtension(strExtension).ToLower(), ".gif") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".jpg") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".jpeg") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".doc") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".docx") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".xls") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".xlsx") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".pdf") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".txt") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".png") != 0
                & string.Compare(Path.GetExtension(strExtension).ToLower(), ".wav") != 0
                )
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        #endregion
    }
}