If you’ve ever wanted to know how something in the .NET Framework does what it does, check out .NET Reflector. This awesome utility will reverse engineer compiled .NET dlls back into C# or VB.NET code. The example below is the reverse-engineered implementation for String.GetHashCode:

public override unsafe int GetHashCode(){      fixed (char* text1 = ((char*) this))      {            char* chPtr1 = text1;            int num1 = 0x15051505;            int num2 = num1;            int* numPtr1 = (int*) chPtr1;            for (int num3 = this.Length; num3 > 0; num3 -= 4)            {                  num1 = (((num1 << 5) + num1) + (num1 >≫ 0x1b)) ^ numPtr1[0];                  if (num3 <= 2)                  {                        break;                  }                  num2 = (((num2 << 5) + num2) + (num2 >> 0x1b)) ^ numPtr1[1];                  numPtr1 += 2;            }            return (num1 + (num2 * 0x5d588b65));      }}

For more information about Lutz Roeder’s .NET Reflector, see the .NET Reflector site.