.NET(C#)代碼效能最佳化

①string ax=string.Empty;     
注:不要使用: string ax="";  I don't konw why.But it's Microsoft's convention.
判斷ax是否為空白:
ax.Length==0   >  ax==string.Empty
    Info         : "To test for empty strings, check if String.Length is
                   equal to zero. Constructs such as "".Equals(someString)
                   and String.Empty.Equals(someString) are less efficient
                   than testing the string length. Replace these with
                   checks for someString.Length == 0."

②Catch{}要捕獲詳細異常,不要再亂拋
catch the specific exception than "System.Exception" or rethrow the exception.
Catching generic exception types can hide run-time problems from the library user,
and can complicate debugging.

③比較字串時不要用.ToLower()   /   .ToUpper()
replace by Equals()     
Don't create a string never used later.
【待續】