C#字符串问题(转录)

  String.Empty != null;
    如果一个TextBox没有值的话,if(TextBox.Text == String.Empty)   ==> 结果为: FALSE
                                                      if(TextBox.Text == String.Empty)   ==> 结果为: TRUE;

    在2.0中判断字符串是否为空String.IsNullOrEmpty(str) == True  则说明字符串为空(null 和 "");

    说明:    “==”只能判断两个字符串的“引用”是否相同;
                要确认两个字符串是否相同请用Equals
                例:
                        string str = "sss"; //str不能为null,可以为"";
                        string strs = null;
                        str.Equals(strs) == false;
                如果str = "";
                        str.Equals(strs) == false;

//获得汉字的区位码
  byte[] array = new byte[2];
  array = System.Text.Encoding.Default.GetBytes("啊");

int i1 = (short)(array[0] - '\0');
  int i2 = (short)(array[1] - '\0');

//unicode解码方式下的汉字码
  array = System.Text.Encoding.Unicode.GetBytes("啊");
  i1 = (short)(array[0] - '\0');
  i2 = (short)(array[1] - '\0');

//unicode反解码为汉字
  string str = "4a55";
  string s1 = str.Substring(0,2);
  string s2 = str.Substring(2,2);

int t1 = Convert.ToInt32(s1,16);
  int t2 = Convert.ToInt32(s2,16);

array[0] = (byte)t1;
  array[1] = (byte)t2;

string s = System.Text.Encoding.Unicode.GetString(array);

//default方式反解码为汉字
  array[0] = (byte)196;
  array[1] = (byte)207;
  s = System.Text.Encoding.Default.GetString(array);

//取字符串长度
  s = "iam方枪枪";
  int len = s.Length;//will output as 6
  byte[] sarr = System.Text.Encoding.Default.GetBytes(s);
  len = sarr.Length;//will output as 3+3*2=9

//字符串相加
  System.Text.StringBuilder sb = new System.Text.StringBuilder("");
  sb.Append("i ");
  sb.Append("am ");
  sb.Append("方枪枪");
0
0
(请您对文章做出评价)

你可能感兴趣的:(字符串)