Can I show file copy progress using FileInfo.CopyTo() in .NET?

The FileInfo.CopyTo is basically a wrapper around the Win32 API call "CopyFile" in the kernel32.dll. This method does not support progress callback.

However, the CopyFileEx method does, and you can write your own .NET wrapper around it in a few minutes, like it is described here: http://www.pinvoke.net/default.aspx/kernel32.CopyFileEx

I also used the implementation provided in the marked answer. However I then created a wrapper to provide a nicer™ API to use from .NET.

Usage:

XCopy.Copy(networkFile.FullPath, temporaryFilename, true, true, (o, pce) => 
{
    worker.ReportProgress(pce.ProgressPercentage, networkFile);
});

Implementation

/// <summary>
/// PInvoke wrapper for CopyEx
/// http://msdn.microsoft.com/en-us/library/windows/desktop/aa363852.aspx
/// </summary>
public class XCopy
{
    public static void Copy(string source, string destination, bool overwrite, bool nobuffering)
    {
         new XCopy().CopyInternal(source, destination, overwrite, nobuffering, null);            
    }

    public static void Copy(string source, string destination, bool overwrite, bool nobuffering, EventHandler<ProgressChangedEventArgs> handler)
    {            
         new XCopy().CopyInternal(source, destination, overwrite, nobuffering, handler);            
    }

    private event EventHandler Completed;
    private event EventHandler<ProgressChangedEventArgs> ProgressChanged;

    private int IsCancelled;
    private int FilePercentCompleted;
    private string Source;
    private string Destination;        

    private XCopy()
    {
        IsCancelled = 0;
    }

    private void CopyInternal(string source, string destination, bool overwrite, bool nobuffering, EventHandler<ProgressChangedEventArgs> handler)
    {
        try
        {
            CopyFileFlags copyFileFlags = CopyFileFlags.COPY_FILE_RESTARTABLE;
            if (!overwrite)
                copyFileFlags |= CopyFileFlags.COPY_FILE_FAIL_IF_EXISTS;

            if (nobuffering)
                copyFileFlags |= CopyFileFlags.COPY_FILE_NO_BUFFERING;

            Source = source;
            Destination = destination;

            if (handler != null)
                ProgressChanged += handler;

            bool result = CopyFileEx(Source, Destination, new CopyProgressRoutine(CopyProgressHandler), IntPtr.Zero, ref IsCancelled, copyFileFlags);
            if (!result)
                throw new Win32Exception(Marshal.GetLastWin32Error());
        }
        catch (Exception)
        {
            if (handler != null)
                ProgressChanged -= handler;

            throw;
        }
    }

    private void OnProgressChanged(double percent)
    {
        // only raise an event when progress has changed
        if ((int)percent > FilePercentCompleted)
        {
            FilePercentCompleted = (int)percent;

            var handler = ProgressChanged;
            if (handler != null)
                handler(this, new ProgressChangedEventArgs((int)FilePercentCompleted, null));
        }
    }

    private void OnCompleted()
    {
        var handler = Completed;
        if (handler != null)
            handler(this, EventArgs.Empty);
    }

    #region PInvoke

    [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CopyFileEx(string lpExistingFileName, string lpNewFileName, CopyProgressRoutine lpProgressRoutine, IntPtr lpData, ref Int32 pbCancel, CopyFileFlags dwCopyFlags);

    private delegate CopyProgressResult CopyProgressRoutine(long TotalFileSize, long TotalBytesTransferred, long StreamSize, long StreamBytesTransferred, uint dwStreamNumber, CopyProgressCallbackReason dwCallbackReason,
                                                    IntPtr hSourceFile, IntPtr hDestinationFile, IntPtr lpData);

    private enum CopyProgressResult : uint
    {
        PROGRESS_CONTINUE = 0,
        PROGRESS_CANCEL = 1,
        PROGRESS_STOP = 2,
        PROGRESS_QUIET = 3
    }

    private enum CopyProgressCallbackReason : uint
    {
        CALLBACK_CHUNK_FINISHED = 0x00000000,
        CALLBACK_STREAM_SWITCH = 0x00000001
    }

    [Flags]
    private enum CopyFileFlags : uint
    {
        COPY_FILE_FAIL_IF_EXISTS = 0x00000001,
        COPY_FILE_NO_BUFFERING = 0x00001000,
        COPY_FILE_RESTARTABLE = 0x00000002,
        COPY_FILE_OPEN_SOURCE_FOR_WRITE = 0x00000004,
        COPY_FILE_ALLOW_DECRYPTED_DESTINATION = 0x00000008
    }

    private CopyProgressResult CopyProgressHandler(long total, long transferred, long streamSize, long streamByteTrans, uint dwStreamNumber,
                                                   CopyProgressCallbackReason reason, IntPtr hSourceFile, IntPtr hDestinationFile, IntPtr lpData)
    {
        if (reason == CopyProgressCallbackReason.CALLBACK_CHUNK_FINISHED)
            OnProgressChanged((transferred / (double)total) * 100.0);

        if (transferred >= total)
            OnCompleted();

        return CopyProgressResult.PROGRESS_CONTINUE;
    }

    #endregion

}