C# getHex函数 输入string (length == 2),输出对应 Int hex;

 public int getHex(string src)
        {
            int hex, hex2;
            string [] buf = new string [2]; buf[0] = src.Substring(0,1);
            buf[1] = src.Substring(1,1);
            
            switch (buf[0])
            {
                case "1": hex = 0x10; break;
                case "2": hex = 0x20; break;
                case "3": hex = 0x30; break;
                case "4": hex = 0x40; break;
                case "5": hex = 0x50; break;
                case "6": hex = 0x60; break;
                case "7": hex = 0x70; break;
                case "8": hex = 0x80; break;
                case "9": hex = 0x90; break;
                case "0": hex = 0x00; break;
                case "a":
                case "A": hex = 0xa0; break;
                case "b":
                case "B": hex = 0xb0; break;
                case "c":
                case "C": hex = 0xc0; break;
                case "d":
                case "D": hex = 0xd0; break;
                case "e":
                case "E": hex = 0xe0; break;
                case "f":
                case "F": hex = 0xf0; break;
                default: return 0;
            } 
            switch (buf[1])
            {
                case "1": hex2 = 0x01; break;
                case "2": hex2 = 0x02; break;
                case "3": hex2 = 0x03; break;
                case "4": hex2 = 0x04; break;
                case "5": hex2 = 0x05; break;
                case "6": hex2 = 0x06; break;
                case "7": hex2 = 0x07; break;
                case "8": hex2 = 0x08; break;
                case "9": hex2 = 0x09; break;
                case "0": hex2 = 0x00; break;
                case "a":
                case "A": hex2 = 0x0a; break;
                case "b":
                case "B": hex2 = 0x0b; break;
                case "c":
                case "C": hex2 = 0x0c; break;
                case "d":
                case "D": hex2 = 0x0d; break;
                case "e":
                case "E": hex2 = 0x0e; break;
                case "f":
                case "F": hex2 = 0x0f; break;
                default: return 0;
            }
            return hex + hex2;  
        }