Format date using variable

Question

Following gives output as 20121212.

DateTime dd = new DateTime(2012, 12, 12);
string val = String.Format("{0:yyyyMMdd}", dd);

And when the format is in a variable. Following does not give above output.

DateTime dd = new DateTime(2012, 12, 12);
string dateFormat = "yyyyMMdd";
string val = String.Format("{0}:{1}", dd, dateFormat);

How can can I achieve it using format in a variable as above?

Answer 1

I believe you have the format in a string variable, May this is what you are looking for:

DateTime dd = new DateTime(2012, 12, 12);
string strFormat = "yyyyMMdd";
string val = String.Format("{0:"+ strFormat + "}", dd);

Answer 2

Just use DateTime.ToString:

string val = dd.ToString( dateFormat );

You are confusing String.Format with your format string which does work only in this way {0:yyyyMMdd}.