c#转换全角半角方法示例

c#全角转换成半角

新建一个项目quanbanjiao，在此项目下新建一个类class1

using system;
using system.web;
using system.text;

namespace quanbanjiao
{
    public class class1
    {
        /**/
        /// <summary>
        /// 判断字符是否英文半角字符或标点
        /// </summary>
        /// <remarks>
        /// 32    空格
        /// 33-47    标点
        /// 48-57    0~9
        /// 58-64    标点
        /// 65-90    a~z
        /// 91-96    标点
        /// 97-122    a~z
        /// 123-126  标点
        /// </remarks>
        public static bool isbjchar(char c)
        {
            int i = (int)c;
            return i >= 32 && i <= 126;
        }

        /**/
        /// <summary>
        /// 判断字符是否全角字符或标点
        /// </summary>
        /// <remarks>
        /// <para>全角字符 - 65248 = 半角字符</para>
        /// <para>全角空格例外</para>
        /// </remarks>
        public static bool isqjchar(char c)
        {
            if (c == '\u3000') return true;

            int i = (int)c - 65248;
            if (i < 32) return false;
            return isbjchar((char)i);
        }

        /// <summary>
        /// 将字符串中的全角字符转换为半角
        /// </summary>
        public static string tobj(string type,string s)
        {
            if (s == null || s.trim() == string.empty) return s;

            stringbuilder sb = new stringbuilder(s.length);
            for (int i = 0; i < s.length; i++)
            {
                if (s[i] == '\u3000')
                    sb.append('\u0020');
                else if (isqjchar(s[i]))
                    sb.append((char)((int)s[i] - 65248));
                else
                    sb.append(s[i]);
            }

            //如果是int类型的，则只能输入int类型，否则自动设为0

            if (type.tolower() == "int")
            {
                try
                {
                    convert.toint32(sb.tostring());
                }
                catch
                {
                    return "0";
                }

            }

 

            //如果是float或double类型的，则只能输入这两种类型，否则自动设为0
            if (type.tolower() == "float" || type.tolower() == "double")
            {
                try
                {
                    convert.todouble(sb.tostring());
                }
                catch
                {
                    return "0";
                }
            }
            return sb.tostring();
        }
    }
}