Date Formate Issue

Question

Currently,I am dynamically creating username like this-

 string initial = txtFirstName.Text.Trim().Substring(0, 1);

        string lastName = txtLastName.Text.Trim();

        string datePart = DateTime.Now.ToString("yyMMdd");

        string userName = initial + lastName + datePart;


But now,Client is aking for DDHHMM Formate.

Anyone have idea about this?


Thanks!