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字符类型转换

char

1   char[] digits = "0123456789abcdef".ToCharArray();

int

   (1)使用强制类型转换:(int)浮点数 

   (2)使用Convert.ToInt32(string)

   (3)使用 int.Parse(string) 或 int.TryParse(string,out int)

 

在实际使用时,当要转换的字符串或数字带有小数时,发现它们有以下区别:

   (1)方法一:截断  方法二:四舍五入   int a=(int)2.8; //结果为2   int b=Convert.ToInt32(2.8); //b的值为3

 (2)int.Parse方法的参数如果不能转换为整数,则报异常。 如 int c=int.Parse("2.8"); //报异常,说明其参数必须是整数字符串

1 //int.TryParse
2 
3 int c = -1;    
4 
5 int.TryParse("2.8", out c); //不能转换成功,结果为0   
6 
7 int.TryParse("2", out c); //转换成功,结果为2

 string to int

1 int a = (int)'a'; //结果为97,注意是字符,而不是字符串(如果是字符串,编译不能通过)         
2 
3 int b = Convert.ToInt32("a"); //报异常 
4 
5 int c=int.Parse("a");  //报异常
6 
7 int d = -1;         
8 
9 int.TryParse("a", out d); //结果为0

 可变字符串

1 string[] HexPadding = new string[16];
2 
3 int padding = HexPadding.Length - i;
4 
5  var buf = new StringBuilder(padding * 3);
6 
7 buf.Append("   ");

 

 

 

 

byte[] + byte[]

 1  /// <summary>
 2         /// 拼接二进制数组
 3         /// </summary>
 4         /// <param name="buffer1"></param>
 5         /// <param name="buffer2"></param>
 6         /// <returns></returns>
 7         public static byte[] Joint(byte[] buffer1, byte[] buffer2)
 8         {
 9             byte[] bufferWhole = new byte[buffer1.Length + buffer2.Length];
10             Buffer.BlockCopy(buffer1, 0, bufferWhole, 0, buffer1.Length);
11             Buffer.BlockCopy(buffer2, 0, bufferWhole, buffer1.Length, buffer2.Length);
12             return bufferWhole;
13         }
14 
15         public static byte[] Joint(byte[] buffer1, byte[] buffer2, byte[] buffer3)
16         {
17             return BufferJointer.Joint(BufferJointer.Joint(buffer1, buffer2), buffer3);
18         }
19 
20         public static byte[] Joint(byte[] buffer1, byte[] buffer2, byte[] buffer3, byte[] buffer4)
21         {
22             return BufferJointer.Joint(BufferJointer.Joint(buffer1, buffer2, buffer3), buffer4);
23         }
24 
25         public static byte[] Joint(byte[] buffer1, byte[] buffer2, byte[] buffer3, byte[] buffer4, byte[] buffer5, byte[] buffer6)
26         {
27             return BufferJointer.Joint(BufferJointer.Joint(buffer1, buffer2, buffer3, buffer4), buffer5, buffer6);
28         }     

 string to byte[] to uft-8

1    public static string get_uft8(string unicodeString)
2    {
3        UTF8Encoding utf8 = new UTF8Encoding();
4        Byte[] encodedBytes = utf8.GetBytes(unicodeString);
5        String decodedString = utf8.GetString(encodedBytes);
6        return decodedString;
7     }

 

 

 

 

 

 

 1   class FileHelper
 2     {
 3         // 首先引用API 函数  
 4 
 5         [DllImport("kernel32.dll")]
 6         private static extern IntPtr _lopen(string lpPathName, int iReadWrite);
 7         [DllImport("kernel32.dll")]
 8         private static extern bool CloseHandle(IntPtr hObject);
 9         private const int OF_READWRITE = 2;
10         private const int OF_SHARE_DENY_NONE = 0x40;
11         private readonly IntPtr HFILE_ERROR = new IntPtr(-1);
12 
13 
14         /// <summary>   
15         /// 检查文件是否已经打开   
16         /// </summary>   
17         /// <param name="strfilepath">要检查的文件路径</param>          
18         /// <returns>-1文件不存在,1文件已经打开,0文件可用未打开</returns>   
19         public FileStatus VerifyFileIsOpen(string strfilepath)
20         {
21             string vFileName = strfilepath;
22 
23             // 先检查文件是否存在,如果不存在那就不检查了   
24             if (!File.Exists(vFileName))
25             {
26                 return FileStatus.Inexistence;
27             }
28 
29             // 打开指定文件看看情况   
30             IntPtr vHandle = _lopen(vFileName, OF_READWRITE | OF_SHARE_DENY_NONE);
31             if (vHandle == HFILE_ERROR)
32             { // 文件已经被打开                   
33                 return FileStatus.Opened;
34             }
35             CloseHandle(vHandle);
36 
37             // 说明文件没被打开,并且可用  
38 
39             return FileStatus.Untapped;
40         }
41     }

 

posted @ 2016-10-28 01:04  Endv  阅读(807)  评论(0编辑  收藏  举报