asp.net string常用操作(1/2)

string s = string.empty;
string s = "";
string s = null;

第一種第一一個指向Null 字元串的字串變數, s不佔用儲存空間.s變數可以使用,比如s.length
.
第二種定義一個指向""的Null 字元串, 佔用一個位元組儲存空間,因為轉義符代表字串結束.s變數可以使用,比如s.length
第三種定義一個指不向任何一個儲存空間的變數,s不可以使用

字串串連:
--------------------------------------------------------------------------------

 
protected void button1_click(object sender, eventargs e)
{
    string str1="abcd", str2="efg";
    str1 += str2;
    response.write(str1); //abcdefg
}

--------------------------------------------------------------------------------

從字串中提取字元:
--------------------------------------------------------------------------------
 

protected void button1_click(object sender, eventargs e)
{
    string str = "abcdefg";
    char c = str[1];   //read only 
    response.write(c); //b
    response.write(str[str.length-1]); //g
}

--------------------------------------------------------------------------------

從字串中遍曆字元:
--------------------------------------------------------------------------------
 

protected void button1_click(object sender, eventargs e)
{
    string str = "abcdefg";
    for (int i = 0; i < str.length; i++)
    {
        response.write(str[i] + "<br/>");
    }
    foreach (char c in str)
    {
        response.write("<hr/>" + c);
    }
}

--------------------------------------------------------------------------------

從字元編碼轉義到字元:
--------------------------------------------------------------------------------
 

protected void button1_click(object sender, eventargs e)
{
    string str = "u4e07u4e00";
    response.write(str); //萬一
}

--------------------------------------------------------------------------------

首頁 1 2 末頁