What does this C# string format mean?

Question

From my previous question, Converting chinese character to Unicode, I had a good answer but with some code I didn't understand:

Console.WriteLine("U+{0:x4}", (int)myChar);

Could anyone explain this?

Answer 1

Console.WriteLine("U+{0:x4}", (int)myChar);

is the equivalent to the call:

Console.WriteLine("U+{0}", ((int)myChar).ToString("x4"));

In a format string, the : indicates that the item should be displayed using the provided format. The x4 part indicates that the integer should be printed in its hexadecimal form using 4 characters. Refer to standard numeric format strings for more information.