Creating an array within a structure

Instance fields within a struct cannot be initialized 'in situ'. They're normally initialized in the constructor, so you could do something like this to create a char[] of a given size:

using System;

class Test
{
    static void Main()
    {
        char[] myArray = new char[]{'H', 'e', 'l', 'l', 'o'};
        MyStruct ms = new MyStruct(myArray);
        Console.WriteLine(new string(ms.MyArray));
        Console.ReadLine();
    }

    struct MyStruct
    {
       private char[] myArray;

       public char[] MyArray
       {
          get {return myArray; }
       }

       public MyStruct(char[] ca)
       {
           myArray = ca;
       }
    }
}

Notice though that you can't fix the size of the char[] field in advance. myArray could be assigned an array of any size.

Similarly, with string fields you can't fix the length in advance. They can be assigned a string of any length.

The only exception to this is if you're using C# 2.0 (or later) in 'unsafe' mode (for interop say). You can then use a fixed size char buffer as explained here:

http://msdn2.microsoft.com/en-us/library/zycewsya(VS.80).aspx