CS1503：参数 1：无法从 'int' 转换为 'byte' C#

Question

private byte[] ParsePatternString(string szPattern)
{
  List<byte> list = new List<byte>();
  foreach ( string text in szPattern.Split(new char[] { ' ' }) )
  {
    list.Add((text == "?") ? 0 : Convert.ToByte(text, 16));
  }
  return list.ToArray();
}

The error happens on list.Add((text == "?")? 0: Convert.ToByte(text, 16)); What I am wondering is how what is creating the error, because based on the other questions about a similar issue I tried and it seems to not have worked.

Answer 1

0 is an int literal. Just like C, there's no way to specify an integer literal smaller than int . The type of a conditional operator is the common type of the two values, thus your expression results in an int expression and can't be passed to a byte argument. You need to cast the expression to byte using either of the following

list.Add(text == "?" ? (byte)0 : Convert.ToByte(text, 16));
list.Add((byte)(text == "?" ? 0 : Convert.ToByte(text, 16)));

Answer 2

You could use byte.MinValue in this case:

private byte[] ParsePatternString(string szPattern)
{
    List<byte> list = new List<byte>();
    foreach ( string text in szPattern.Split(new char[] { ' ' }) )
    {
        list.Add(text == "?" ? byte.MinValue : Convert.ToByte(text, 16));
    }
    return list.ToArray();
}

Answer 3

I have actually never used CSharp before but I think the problem might be that it reads 0 as an int and not a Boolean, and doesn't automatically convert it. From what I'm reading about it you need to add an explicit cast like this:

list.Add((text == "?") ? (byte) 0 : Convert.ToByte(text, 16));