CompareDateTime、CompareDate、CompareTime、SameDateTime、SameDate、SameTime - 对比时间的函数

CompareDateTime、CompareDate、CompareTime 返回的是 -1、0、1;
前者 = 后者: 返回 0;
前者 > 后者: 返回 1;
前者 < 后者: 返回 -1;

SameDateTime、SameDate、SameTime 返回的是 True 和 False.

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

    procedure FormCreate(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses DateUtils;



procedure TForm1.FormCreate(Sender: TObject);

var

  t1,t2: TDateTime;

  r1,r2,r3: Integer;

  b1,b2,b3: Boolean;

begin

  {日期一致、时间不一致}

  t1 := StrToDateTime('2009-5-20 1:1:1');

  t2 := StrToDateTime('2009-5-20 1:0:0');



  r1 := CompareDateTime(t1, t2); //1

  r2 := CompareDate(t1, t2);     //0

  r3 := CompareTime(t1, t2);     //1



  b1 := SameDateTime(t1, t2);    //False

  b2 := SameDate(t1, t2);        //True

  b3 := SameTime(t1, t2);        //False



  {日期不一致、时间一致}

  t1 := StrToDateTime('2009-5-20 1:1:1');

  t2 := StrToDateTime('2009-5-21 1:1:1');



  r1 := CompareDateTime(t1, t2); //-1

  r2 := CompareDate(t1, t2);     //-1

  r3 := CompareTime(t1, t2);     //0



  b1 := SameDateTime(t1, t2);    //False

  b2 := SameDate(t1, t2);        //False

  b3 := SameTime(t1, t2);        //True



  {日期、时间都不一致}

  t1 := StrToDateTime('2009-5-19 1:1:1');

  t2 := StrToDateTime('2009-5-20 0:0:0');



  r1 := CompareDateTime(t1, t2); //-1

  r2 := CompareDate(t1, t2);     //-1

  r3 := CompareTime(t1, t2);     //1



  b1 := SameDateTime(t1, t2);    //False

  b2 := SameDate(t1, t2);        //False

  b3 := SameTime(t1, t2);        //False

end;



end.

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DateUtils-Function

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