String must be exactly one character long

Question

I have what I think is an easy problem. For some reason the following code generates the exception, \"String must be exactly one character long\".

int n = 0;
for         


        

Answer 1

Convert.ToChar( string s ), per the documentation requires a single character string, otherwise it throws a FormatException as you've noted. It is a rough, though more restrictive, equivalent of

public char string2char( string s ) { return s[0] ; }

Your code does the following:

• Iterates over all the characters in some enumrable collection of characters.
• For each such character, it...
  • Converts the char to an int. Hint: a char is an integral type: its an unsigned 16-bit integral value.
  • converts that value to a string containing a hex representation of the character in question. For most characters, that string will be at least two character in length: for instance, converting the space character (' ', 0x20) this way will give you the string "20".
  • You then try to convert that back to a char and replace the current item being iterated over. This is where your exception is thrown. One thing you should note here is that altering a collection being enumerated is likely to cause the enumerator to throw an exception.

What exactly are you trying to accomplish here. For instance, given a charMsg that consist of 3 characters, 'a', 'b' and 'c', what should happen. A clear problem statement helps us to help you.