Problem updating the list with date time type

[john121]

Hi
I am trying to update my document library list item and for some reason this is not updating.

I think the problem lies in docdate, which is of datetime type. I have tried with various date formats but no luck so far.

could any one please let me know what i am doing wrong here.

here is the code i am using

string strTest = "2/16/1992 12:15:12";  
DateTime docdate= DateTime.Parse(strTest);


// Create CAML script to update list item 
String sBatch = String.Format(@"<Method ID='1' Cmd='Update'>" 
+ @"<Field Name='ID'>{0}</Field>" 
+ @"<Field Name='FileRef'>{1}</Field>" 
+ @"<Field Name='FromEmailAddress'>{2}</Field>" 
+ @"<Field Name='DocumentDate'>{3}</Field>" 
+ @"</Method>", id, url, email, docdate);

thanks for any help