Quick question: One of my forms in my winform app (c#) makes an async call to a WCF service to get some data. If the form happens to close before the callback happens, it crashes with an error about accessing a disposed object. What's the correct way to check/handle this situation? The error happens on the Invoke call to the method to update my form, but I can't drill down to the inner exception because it says the code has been optimized.

The Code:

  public void RequestUserPhoto(int userID)
        {
            WCF.Service.BeginGetUserPhoto(userID,
                new AsyncCallback(GetUserPhotoCB), userID);
        }

    public void GetUserPhotoCB(IAsyncResult result)
    {
        var photo = WCF.Service.EndGetUserPhoto(result);
        int userID = (int)result.AsyncState;
        UpdateUserPhoto(userID, photo);
    }

    public delegate void UpdateUserPhotoDelegate(int userID, Binary photo);
    public void UpdateUserPhoto(int userID, Binary photo)
    {
        if (InvokeRequired)
        {
            var d = new UpdateUserPhotoDelegate(UpdateUserPhoto);
            Invoke(d, new object[] { userID, photo });
        }
        else
        {
            if (photo != null)
            {
                var ms = new MemoryStream(photo.ToArray());
                var bmp = new System.Drawing.Bitmap(ms);
                if (userID == theForm.AuthUserID)
                {
                    pbMyPhoto.BackgroundImage = bmp;
                }
                else
                {
                    pbPhoto.BackgroundImage = bmp;
                }
            }
        }
    }