Date Formats

In C#.Net we can use GetDateTimeFormats() function.

DateTime.Now.GetDateTimeFormats('d')[x]

[0] "10/4/2007" string
[1] "10/4/07" string
[2] "10/04/07" string
[3] "10/04/2007" string
[4] "07/10/04" string
[5] "2007-10-04" string
[6] "04-Oct-07" string

So for a simple test :

if(p.StartDate <= Convert.ToDateTime(DateTime.Now.GetDateTimeFormats('d')[3]))

We also have the ToString() Method

All the patterns:
0	MM/dd/yyyy	01/31/2011
1	dddd, dd MMMM yyyy	Monday, 31 January 2011
2	dddd, dd MMMM yyyy HH:mm	Monday, 31 January 2011 17:48
3	dddd, dd MMMM yyyy hh:mm tt	Monday, 31 January 2011 05:48 PM
4	dddd, dd MMMM yyyy H:mm	Monday, 31 January 2011 17:48
5	dddd, dd MMMM yyyy h:mm tt	Monday, 31 January 2011 5:48 PM
6	dddd, dd MMMM yyyy HH:mm:ss	Monday, 31 January 2011 17:48:23
7	MM/dd/yyyy HH:mm	01/31/2011 17:48
8	MM/dd/yyyy hh:mm tt	01/31/2011 05:48 PM
9	MM/dd/yyyy H:mm	01/31/2011 17:48
10	MM/dd/yyyy h:mm tt	01/31/2011 5:48 PM
11	MM/dd/yyyy HH:mm:ss	01/31/2011 17:48:23
12	MMMM dd	January 31
13	MMMM dd	January 31
14	yyyy'-'MM'-'dd'T'HH':'mm':'ss.fffffffK	2011-01-31T17:48:23.0232229-05:00
15	yyyy'-'MM'-'dd'T'HH':'mm':'ss.fffffffK	2011-01-31T17:48:23.0232229-05:00
16	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'	Mon, 31 Jan 2011 17:48:23 GMT
17	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'	Mon, 31 Jan 2011 17:48:23 GMT
18	yyyy'-'MM'-'dd'T'HH':'mm':'ss	2011-01-31T17:48:23
19	HH:mm	17:48
20	hh:mm tt	05:48 PM
21	H:mm	17:48
22	h:mm tt	5:48 PM
23	HH:mm:ss	17:48:23
24	yyyy'-'MM'-'dd HH':'mm':'ss'Z'	2011-01-31 17:48:23Z
25	dddd, dd MMMM yyyy HH:mm:ss	Monday, 31 January 2011 17:48:23
26	yyyy MMMM	2011 January
27	yyyy MMMM	2011 January

The patterns for DateTime.ToString ( 'd' ) :
0	MM/dd/yyyy	01/31/2011

The patterns for DateTime.ToString ( 'D' ) :
0	dddd, dd MMMM yyyy	Monday, 31 January 2011

The patterns for DateTime.ToString ( 'f' ) :
0	dddd, dd MMMM yyyy HH:mm	Monday, 31 January 2011 17:48
1	dddd, dd MMMM yyyy hh:mm tt	Monday, 31 January 2011 05:48 PM
2	dddd, dd MMMM yyyy H:mm	Monday, 31 January 2011 17:48
3	dddd, dd MMMM yyyy h:mm tt	Monday, 31 January 2011 5:48 PM

The patterns for DateTime.ToString ( 'F' ) :
0	dddd, dd MMMM yyyy HH:mm:ss	Monday, 31 January 2011 17:48:23

The patterns for DateTime.ToString ( 'g' ) :
0	MM/dd/yyyy HH:mm	01/31/2011 17:48
1	MM/dd/yyyy hh:mm tt	01/31/2011 05:48 PM
2	MM/dd/yyyy H:mm	01/31/2011 17:48
3	MM/dd/yyyy h:mm tt	01/31/2011 5:48 PM

The patterns for DateTime.ToString ( 'G' ) :
0	MM/dd/yyyy HH:mm:ss	01/31/2011 17:48:23

The patterns for DateTime.ToString ( 'm' ) :
0	MMMM dd	January 31

The patterns for DateTime.ToString ( 'r' ) :
0	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'	Mon, 31 Jan 2011 17:48:23 GMT

The patterns for DateTime.ToString ( 's' ) :
0	yyyy'-'MM'-'dd'T'HH':'mm':'ss	2011-01-31T17:48:23

The patterns for DateTime.ToString ( 'u' ) :
0	yyyy'-'MM'-'dd HH':'mm':'ss'Z'	2011-01-31 17:48:23Z

The patterns for DateTime.ToString ( 'U' ) :
0	dddd, dd MMMM yyyy HH:mm:ss	Monday, 31 January 2011 17:48:23

The patterns for DateTime.ToString ( 'y' ) :
0	yyyy MMMM	2011 January