SidebarLibrary.WinControls.OutlookBar.AnimateScroll C# (CSharp) Method

		void AnimateScroll(int From, int To)
		{
			if (currentBandIndex == -1 || bands.Count == 0)
				return;

			//OutlookBarBand band = bands[currentBandIndex];
			// Make sure we are whithin bounds
			Debug.Assert(From >= 0 && From < bands.Count);
			Debug.Assert(To >= 0 && To < bands.Count);

			// Get needed dimensions
			Rectangle viewPortRect = GetViewPortRect();
			Rectangle headerRect = new Rectangle(0, 0, viewPortRect.Width, BAND_HEADER_HEIGHT);
			Rectangle drawingRect = new Rectangle(0, 0, viewPortRect.Width, viewPortRect.Height + headerRect.Height * 2);

			// Use straight GDI to do the drawing
			IntPtr hDC = WindowsAPI.GetDC(Handle);
			IntPtr hDCFrom = WindowsAPI.CreateCompatibleDC(hDC);
			IntPtr hDCTo = WindowsAPI.CreateCompatibleDC(hDC);
			IntPtr bmFrom = WindowsAPI.CreateCompatibleBitmap(hDC, drawingRect.Width, drawingRect.Height);
			IntPtr bmTo = WindowsAPI.CreateCompatibleBitmap(hDC, drawingRect.Width, drawingRect.Height);

			// Select in the drawing surface
			//IntPtr hOldFromBitmap = WindowsAPI.SelectObject(hDCFrom, bmFrom);
			//IntPtr hOldToBitmap = WindowsAPI.SelectObject(hDCTo, bmTo);

			// Draw in the memory device context
			using (Graphics gHeaderDC = Graphics.FromHdc((To > From) ? hDCTo : hDCFrom))
			{
				DrawBandBitmap(hDCFrom, bands[From], From, drawingRect);
				DrawBandBitmap(hDCTo, bands[To], To, drawingRect);
				DrawHeader(gHeaderDC, To, new Rectangle(drawingRect.Left, drawingRect.Top,
					drawingRect.Width, drawingRect.Top + BAND_HEADER_HEIGHT), Border3DStyle.RaisedInner);

				Rectangle rectFrom = GetHeaderRect(From);
				Rectangle rectTo = GetHeaderRect(To);
				int headerHeight = rectFrom.Height;

				// Do the animation with the bitmaps
				if (To > From)
				{
					for (int y = rectTo.Top - headerHeight; y > rectFrom.Bottom; y -= headerHeight)
					{
						// Draw From bitmap
						WindowsAPI.BitBlt(hDC, viewPortRect.Left, rectFrom.Bottom + 1,
							viewPortRect.Width, y - rectFrom.Bottom - 1, hDCFrom, 0, 0, (int)PatBltTypes.SRCCOPY);

						// Draw To Bitmap
						WindowsAPI.BitBlt(hDC, viewPortRect.Left, y, viewPortRect.Width,
							viewPortRect.Bottom - y + headerHeight, hDCTo, 0, 0, (int)PatBltTypes.SRCCOPY);
						Thread.Sleep(animationSpeed);
					}
				}
				else
				{
					Rectangle rcTo = new Rectangle(viewPortRect.Left,
						viewPortRect.Bottom, viewPortRect.Width, viewPortRect.Bottom - headerHeight);
					for (int y = rectFrom.Top + 1; y < rcTo.Top - headerHeight; y += headerHeight)
					{

						// Draw To Bitmap
						WindowsAPI.BitBlt(hDC, viewPortRect.Left, rectFrom.Top, viewPortRect.Width,
							y - rectFrom.Top - 1, hDCTo, 0, 0, (int)PatBltTypes.SRCCOPY);

						// Draw From bitmap
						WindowsAPI.BitBlt(hDC, viewPortRect.Left, y,
							viewPortRect.Width, viewPortRect.Bottom - y, hDCFrom, 0, 0, (int)PatBltTypes.SRCCOPY);
						Thread.Sleep(animationSpeed);

					}
				}
			}

			// Cleanup
			WindowsAPI.ReleaseDC(Handle, hDC);
			WindowsAPI.DeleteDC(hDCFrom);
			WindowsAPI.DeleteDC(hDCTo);
			WindowsAPI.SelectObject(hDCFrom, bmFrom);
			WindowsAPI.SelectObject(hDCTo, bmTo);
			WindowsAPI.DeleteObject(bmFrom);
			WindowsAPI.DeleteObject(bmTo);
		}