Can I "multiply" a string (in C#)?

In .NET 4 you can do this:

String.Concat(Enumerable.Repeat("Hello", 4))

Unfortunately / fortunately, the string class is sealed so you can't inherit from it and overload the * operator. You can create an extension method though:

public static string Multiply(this string source, int multiplier)
{
   StringBuilder sb = new StringBuilder(multiplier * source.Length);
   for (int i = 0; i < multiplier; i++)
   {
       sb.Append(source);
   }

   return sb.ToString();
}

string s = "</li></ul>".Multiply(10);

Note that if your "string" is only a single character, there is an overload of the string constructor to handle it:

int multipler = 10;
string TenAs = new string ('A', multipler);