(Delphi DLL) Compute Difference Between Two DateTime Strings

Demonstrates how to compute the difference between two datetime strings.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, CkDateTime, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
t1: PWideChar;
t2: PWideChar;
sb1: HCkStringBuilder;
count: Integer;
sb2: HCkStringBuilder;
dt1: HCkDateTime;
dt2: HCkDateTime;
diffSeconds: Integer;

begin
// Imagine we have these strings:

t1 := '2022-11-14 15:45:38';
t2 := '2022-11-16 17:23:41';

// How many minutes are between the two?

// First, we'd want load each date/time into a Chilkat CkDateTime object.
// In this case, there are no CkDateTime methods that accept the above format.
// However.. the CkDateTime's SetFromTimestamp will accept a date in the format "YYYY-MM-DDThh:mm:ssZ"

// First modify the above dates to the timestamp format.
sb1 := CkStringBuilder_Create();
CkStringBuilder_Append(sb1,t1);
count := CkStringBuilder_Replace(sb1,' ','T');
CkStringBuilder_Append(sb1,'Z');

sb2 := CkStringBuilder_Create();
CkStringBuilder_Append(sb2,t2);
count := CkStringBuilder_Replace(sb2,' ','T');
CkStringBuilder_Append(sb2,'Z');

// Load each into a CkDateTime
dt1 := CkDateTime_Create();
CkDateTime_SetFromTimestamp(dt1,CkStringBuilder__getAsString(sb1));
// verify...
Memo1.Lines.Add(CkDateTime__getAsTimestamp(dt1,False));

dt2 := CkDateTime_Create();
CkDateTime_SetFromTimestamp(dt2,CkStringBuilder__getAsString(sb2));
// verify...
Memo1.Lines.Add(CkDateTime__getAsTimestamp(dt2,False));

// Get the difference in seconds
diffSeconds := CkDateTime_DiffSeconds(dt2,dt1);
Memo1.Lines.Add('Difference in seconds: ' + IntToStr(diffSeconds));
Memo1.Lines.Add('Difference in minutes: ' + IntToStr(diffSeconds / 60));

CkStringBuilder_Dispose(sb1);
CkStringBuilder_Dispose(sb2);
CkDateTime_Dispose(dt1);
CkDateTime_Dispose(dt2);

end;