C#里面全角和半角的自由转换

 1、半角转全角

 1c = "hello World".ToCharArray();
 2            for(int i = 0; i < c.Length; i++)
 3            {
 4                byte[] b = System.Text.Encoding.Unicode.GetBytes(c,i,1);
 5                if(b.Length == 2)
 6                {
 7                    if(b[1] == 0)
 8                    {
 9                        b[0]=(byte)(b[0]-32);
10                        b[1]=255;
11                        c[i]=System.Text.Encoding.Unicode.GetChars(b)[0];
12                    }
13                }
14            }
15            string strNew=new string(c);
16

2、全角转半角

 1string QJstr = "hello，Amigo  quanjiao字符";
 2            char[] c = QJstr.ToCharArray();
 3            for(int i = 0; i < c.Length; i++)
 4            {
 5                byte[] b = System.Text.Encoding.Unicode.GetBytes(c,i,1);
 6                if(b.Length == 2)
 7                {
 8                    if(b[1] == 255)
 9                    {
10                        b[0] =(byte)(b[0]+32);
11                        b[1] = 0;
12                        c[i] = System.Text.Encoding.Unicode.GetChars(b)[0];
13                    }
14                }
15            }
16            string strNew=new string(c);

3、其他方法

 1 半全角互换#region 半全角互换
 2        /**//// <summary>
 3        /// 转全角的函数(SBC case)
 4        /// </summary>
 5        /// <param name="input">任意字符串</param>
 6        /// <returns>全角字符串</returns>
 7        ///<remarks>
 8        ///全角空格为12288，半角空格为32
 9        ///其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
10        ///</remarks>        
11        public static string ToSBC(string input)
12        {
13            //半角转全角：
14            char[] c = input.ToCharArray();
15            for (int i = 0; i < c.Length; i++)
16            {
17                if (c[i] == 32)
18                {
19                    c[i] = (char)12288;
20                    continue;
21                }
22                if (c[i] < 127 && c[i] > 32)
23                {
24                    c[i] = (char)(c[i] + 65248);
25                }
26            }
27            return new string(c);
28        }
29
30        /**//// <summary>
31        /// 转半角的函数(DBC case)
32        /// </summary>
33        /// <param name="input">任意字符串</param>
34        /// <returns>半角字符串</returns>
35        ///<remarks>
36        ///全角空格为12288，半角空格为32(此处不必转空格)
37        ///其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
38        ///</remarks>
39        public static string ToDBC(string input)
40        {
41            char[] c = input.ToCharArray();
42            for (int i = 0; i < c.Length; i++)
43            {
44                if (c[i] == 12288)
45                {
46                    c[i] = (char)32;
47                    continue;
48                }
49                if (c[i] > 65280 && c[i] < 65375)
50                {
51                    c[i] = (char)(c[i] - 65248);
52                }
53            }
54            return new string(c);
55        }
56        #endregion
57

转：http://www.haoyu63.com/article.asp?id=33