??
鏄?/p>
C#2.0
涓柊澧炵殑涓�涓繍绠楃锛?/p>
鍙互璁や负鏄笁鍏冩搷浣滅
?:
鐨勭畝鐗堬紝
鍏朵富瑕佷綔鐢ㄦ槸濡傛灉
??
杩愮畻绗︾殑宸︽搷浣滄暟闈炵┖锛?/p>
璇ヨ繍绠楃灏嗚繑鍥炲乏鎿嶄綔鏁帮紝
鍚﹀垯杩斿洖鍙虫搷浣滄暟銆?/p>
濡傛灉鑳借緝濂藉湴浣跨敤
姝ゆ搷浣滅锛屽皢浼氬緱鍒版剰鎯充笉鍒扮殑鏁堟灉銆?/p>
public class Program
{
class MyClass {}
static MyClass instance;
static void Main()
{
//
濡傛灉
instance == null,
鍒欏仛鍒濆鍖?/p>
//
甯歌鍐欐硶
:
if(instance == null)
{
instance = new MyClass();
}
//
浣跨敤
??
鐨勫啓娉?/p>
:
instance = instance ?? new MyClass();
}
}
涔熷彲浠ョ敤浜庡嚱鏁扮殑杩斿洖鍊间腑锛?/p>
public class Program
{
public string Str1 { get; set; }
public string Str2 { get; set; }
public string Str3 { get; set; }
//
濡傛灉
Str1
涓嶄负
NULL
杩斿洖
Str1,
鍚﹀垯
Str2,
浠ユ绫绘帹
public override string ToString()
{
//if-else
甯歌鍐欐硶
if (Str1 != null)
{
return Str1;
}
else if (Str2 != null)
{
return Str2;
}
else if (Str3 != null)
{
return Str3;
}
else
{
return base.ToString();