C# string和byte[]的转换

转自 http://www.cnblogs.com/Mainz/archive/2008/04/09/String_Byte_Array_Convert_CSharp.html

string类型转成byte[]：

byte[] byteArray = System.Text.Encoding.Default.GetBytes ( str );

反过来，byte[]转成string：

string str = System.Text.Encoding.Default.GetString ( byteArray );

其它编码方式的，如System.Text.UTF8Encoding，System.Text.UnicodeEncoding class等；例如：

string类型转成ASCII byte[]：（"01" 转成 byte[] = new byte[]{ 0x30, 0x31}）

byte[] byteArray = System.Text.Encoding.ASCII.GetBytes ( str );

ASCII byte[] 转成string：（byte[] = new byte[]{ 0x30, 0x31} 转成 "01"）

string str = System.Text.Encoding.ASCII.GetString ( byteArray );

有时候还有这样一些需求：

byte[] 转成原16进制格式的string，例如0xae00cf, 转换成 "ae00cf"；new byte[]{ 0x30, 0x31}转成"3031":

 public static string ToHexString ( byte[] bytes ) // 0xae00cf => "AE00CF "
        {
            string hexString = string.Empty;
            if ( bytes != null )
            {
                StringBuilder strB = new StringBuilder ();

                for ( int i = ; i < bytes.Length; i++ )
                {
                    strB.Append ( bytes[i].ToString ( "X2" ) );
                }
                hexString = strB.ToString ();
            }
            return hexString;
        }

反过来，16进制格式的string 转成byte[]，例如, "ae00cf"转换成0xae00cf，长度缩减一半；"3031" 转成new byte[]{ 0x30, 0x31}:

public static byte[] GetBytes(string hexString, out int discarded)
        {
            discarded = ;
            string newString = "";
            char c;
            // remove all none A-F, 0-9, characters
            for (int i=; i<hexString.Length; i++)
            {
                c = hexString[i];
                if (IsHexDigit(c))
                    newString += c;
                else
                    discarded++;
            }
            // if odd number of characters, discard last character
            if (newString.Length %  != )
            {
                discarded++;
                newString = newString.Substring(, newString.Length-);
            }

            int byteLength = newString.Length / ;
            byte[] bytes = new byte[byteLength];
            string hex;
            int j = ;
            for (int i=; i<bytes.Length; i++)
            {
                hex = new String(new Char[] {newString[j], newString[j+]});
                bytes[i] = HexToByte(hex);
                j = j+;
            }
            return bytes;
        }

转自 http://www.cnblogs.com/Mainz/archive/2008/04/09/String_Byte_Array_Convert_CSharp.html