這裏顯示兩個版本的差異處。
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visual_c_sharp [2024/04/08 08:59] don 建立 |
visual_c_sharp [2024/06/25 15:03] (目前版本) don [string] |
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====== Visual C# 研究 ====== | ====== Visual C# 研究 ====== | ||
+ | |||
+ | |||
+ | ==== string ==== | ||
+ | < | ||
+ | string a = " | ||
+ | string b = @" | ||
+ | string c = "hello \t world"; | ||
+ | string d = @" | ||
+ | string e = "Joe said \" | ||
+ | string f = @"Joe said "" | ||
+ | string g = " | ||
+ | string h = @" | ||
+ | string i = " | ||
+ | string j = @"one | ||
+ | two | ||
+ | three"; | ||
+ | </ | ||
+ | |||
+ | 上面是msdn給的例子, | ||
+ | 基本上加上@就是告訴編譯器, | ||
+ | 如果你不加@, | ||
+ | 而使用@要注意的是上例的string f, | ||
+ | |||
+ | |||
+ | C# @符號(小老鼠)的用處 | ||
+ | |||
+ | 1.限定跳脫字串 | ||
+ | 用 @ 符號加在字串前面表示其中的轉義字元“不”被處理。 | ||
+ | 例如" | ||
+ | 如果使用@符號就會比較簡單: string fileName= @" | ||
+ | |||
+ | 2.讓字串連接跨行 | ||
+ | 不使用@符號,一種寫法是這樣的: | ||
+ | < | ||
+ | string strSQL= " | ||
+ | " INNER JOIN Person.Contact AS c" + " ON e.ContactID = c.ContactID" | ||
+ | " ORDER BY c.LastName"; | ||
+ | </ | ||
+ | 加上@符號後就可以直接換行了: | ||
+ | < | ||
+ | string strSQL= @" | ||
+ | INNER JOIN Person.Contact AS c | ||
+ | ON e.ContactID = c.ContactID | ||
+ | ORDER BY c.LastName"; | ||
+ | </ | ||
+ | 3.在識別字中的用法 | ||
+ | C# | ||
+ | < | ||
+ | 例如 string @string=" | ||
+ | int @int = 123456789; | ||
+ | </ | ||
+ | 來自 < | ||
+ | |||