C#.net2.0中字母与ascii码之间转换的问题,高手请进

//字符转数字
public static int Asc(string character)
{
if (character.Length == 1)
{
System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding();
int intAsciiCode = (int)asciiEncoding.GetBytes(character)[0];
return (intAsciiCode);
}
else
{
throw new Exception("Character is not valid.");
}

}

//ASCII码转字符：

public static string Chr(int asciiCode)
{
if (asciiCode >= 0 && asciiCode <= 255)
{
System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding();
byte[] byteArray = new byte[] { (byte)asciiCode };
string strCharacter = asciiEncoding.GetString(byteArray);
return (strCharacter);
}
else
{
throw new Exception("ASCII Code is not valid.");
}
}

1、int j=(int)System.Text.Encoding.ASCII.GetBytes(s)[0];//获取AS