Utils

Mix two hash code to produce a new hash code

Code
/**//// <summary>
        /// Mix two hash code to produce a new hash code.
        /// </summary>
        public static int MixCodes(int code1, int code2) {
            int h = (code1 << 4) + code2;
            int g = h & unchecked((int)0xF0000000);
            if (g != 0)
                h ^= g >> 24;
            h &= ~g;
            return h;
        }

消影：

消影
[DllImport(/**//*MSG0*/"user32.dll", CharSet = CharSet.Auto)]
public static extern int SendMessage(
    IntPtr hWnd,
    [MarshalAs(UnmanagedType.U4)] uint Msg,
    IntPtr wParam,
    IntPtr lParam);

private void BeginPaint()
{
   SendMessage(this.Handle, WM_SETREDRAW, (IntPtr)0, IntPtr.Zero);
}

private void EndPaint()
{
    SendMessage(this.Handle, WM_SETREDRAW, (IntPtr)1, IntPtr.Zero);
    this.Refresh();
} 

忘记加的WM_SETREDRAW值了：
 public const int  WM_SETREDRAW                    = 0x000B;

抓起Dump文件：

 [DllImport("DbgHelp.dll")]
        private static extern Boolean MiniDumpWriteDump(
                                    IntPtr hProcess,
                                    Int32 processId,
                                    IntPtr fileHandle,
                                    MiniDumpType dumpType, 
                                    ref MinidumpExceptionInfo excepInfo,
                                    IntPtr userInfo, 
                                    IntPtr extInfo );

详细可见：如何让程序抓到dump文件，MiniDumpWriteDump 一文

Timer (摘自 《CLR Via C#》) 

 // This class is useful for doing operation performance timing
 internal sealed class OperationTimer : IDisposable
 {
     private Int64 m_startTime;
     private String m_text;
     private Int32 m_collectionCount;
     public OperationTimer(String text)
     {
         PrepareForOperation();
         m_text = text;
         m_collectionCount = GC.CollectionCount(0);
         // This should be the last statement in this
         // method to keep timing as accurate as possible
         m_startTime = Stopwatch.GetTimestamp();
     }
     public void Dispose()
     {
         Console.WriteLine("{0,6:###.00} seconds (GCs={1,3}) {2}", (Stopwatch.GetTimestamp() - m_startTime) / (Double)Stopwatch.Frequency,
                                                                    GC.CollectionCount(0) - m_collectionCount, m_text);
     }
     private static void PrepareForOperation()
     {
         GC.Collect();
         GC.WaitForPendingFinalizers();
         GC.Collect();
     }
 }