Instance 365 (8) --------- three methods to format a string as a date

I. DateTime. ParseExact method,

Ii. Code

Using System; using System. collections. generic; using System. componentModel; using System. data; using System. drawing; using System. linq; using System. text; using System. windows. forms; namespace ConvertToString {public partial class Frm_Main: Form {public Frm_Main () {InitializeComponent ();} private void btn_Convert_Click (object sender, EventArgs e) {/* DateTime. parseExac parameter s type: System. string contains the date and time to be converted. Format type: System. String is used to define the format specifiers of the desired s format. For more information, see the "Remarks" section. Provider type: System. IFormatProvider, an object that provides information about the specific format of s. Return Value Type: System. DateTime is an object. It is equivalent to the date and time contained in s, which is specified by format and provider. */# Region for Windows 7 system string s = string. format ("{0}/{1}/{2}", // obtain the date string txt_Year.Text, txt_Month.Text, txt_Day.Text); DateTime P_dt = DateTime. parseExact (// convert the string to the date format s, "yyyy/MM/dd", null ); # endregion // # region for Windows XP or 2003 systems // string s = string. format ("{0} {1} {2}", // obtain the date string // txt_Year.Text, txt_Month.Text, txt_Day.Text); // DateTime P_dt = DateTime. parseExact (// convert string to date format //, "yyyyMMd D ", null); // # endregion MessageBox. Show (" input date: "// pop-up message dialog box + P_dt.ToLongDateString ()," prompt! ");}}}

3. DateTime. ToString format date,

4. Code

Using System; using System. collections. generic; using System. componentModel; using System. data; using System. drawing; using System. linq; using System. text; using System. windows. forms; namespace TmrFormat {public partial class Frm_Main: Form {public Frm_Main () {InitializeComponent ();} /* parameter format detailed usage format character Association attributes/description d ShortDatePattern D LongDatePattern f complete date and time (long date and short time) F FullDateTimePattern (long date and long time) g regular (short date and short time) G regular (short date and long time) m, M MonthDayPattern r, R RFC1123Pattern s use local time SortableDateTimePattern (based on ISO 8601) t ShortTimePattern T LongTimePattern u UniversalSortableDateTimePattern is used to display the format of Universal Time U use the complete date and time of Universal Time (long date and long time) y, Y YearMonthPattern */private void btn_GetTime_Click (object sender, EventArgs e) {lab_time.Text = DateTime. now. toString ("d") + "\ n" + // format the DateTime string using the string variable in the specified format. now. toString ("D") + "\ n" + DateTime. now. toString ("f") + "\ n" + DateTime. now. toString ("F") + "\ n" + DateTime. now. toString ("g") + "\ n" + DateTime. now. toString ("G") + "\ n" + DateTime. now. toString ("R") + "\ n" + DateTime. now. toString ("y") + "\ n" + "current system time:" + DateTime. now. toString (// format the string in the custom format "yyyy MM dd HH mm ss seconds ");}}}

V. Convert. ToDateTime mode,

Vi. Code

Using System; using System. collections. generic; using System. componentModel; using System. data; using System. drawing; using System. linq; using System. text; using System. windows. forms; namespace ConvertToString {public partial class Frm_Main: Form {public Frm_Main () {InitializeComponent ();} private void btn_Convert_Click (object sender, EventArgs e) {/* parameter value type: system. string Representation of the date and time. Return value Type: Date and time equivalent of System. DateTime value. If value is null, it is the date and time equivalent of DateTime. MinValue. */String P_DateTime = string. format ("{0}/{1}/{2}", // obtain the date string txt_Year.Text, txt_Month.Text, txt_Day.Text); DateTime P_dt = Convert. toDateTime (P_DateTime); MessageBox. show ("input date:" // pop-up message dialog box + P_dt.ToLongDateString (), "prompt! ");}}}