Delphi DLL

Find a ZIP Entry by EntryID Using EntryById

See more Zip Examples

This example demonstrates how to use the EntryById method to retrieve a ZIP entry using its unique EntryID.

Each ZipEntry object has an EntryID property that uniquely identifies the entry within the currently open ZIP object.

This is useful when:

• An application stores EntryID values for later use
• ZIP entries need to be retrieved without searching by filename
• Multiple entries may have similar names or paths

The example:

• Opens a ZIP archive
• Retrieves an entry using EntryAt
• Saves the entry's EntryID
• Uses EntryById to retrieve the same entry later

Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
zip: HCkZip;
entry: HCkZipEntry;
entryId: Integer;
entry2: HCkZipEntry;

begin
success := False;

success := False;

// Open an existing ZIP archive.
zip := CkZip_Create();

success := CkZip_OpenZip(zip,'example.zip');
if (success = False) then
  begin
    Memo1.Lines.Add(CkZip__lastErrorText(zip));
    Exit;
  end;

// Retrieve the first entry in the ZIP archive.
entry := CkZipEntry_Create();

success := CkZip_EntryAt(zip,0,entry);
if (success = False) then
  begin
    Memo1.Lines.Add(CkZip__lastErrorText(zip));
    Exit;
  end;

Memo1.Lines.Add('Original entry:');
Memo1.Lines.Add('  FileName: ' + CkZipEntry__fileName(entry));
Memo1.Lines.Add('  EntryID: ' + IntToStr(CkZipEntry_getEntryID(entry)));
Memo1.Lines.Add('');

// Save the EntryID for later use.
entryId := CkZipEntry_getEntryID(entry);

// Create another ZipEntry object.
entry2 := CkZipEntry_Create();

// Retrieve the same entry using EntryById.
success := CkZip_EntryById(zip,entryId,entry2);
if (success = False) then
  begin
    Memo1.Lines.Add(CkZip__lastErrorText(zip));
    Exit;
  end;

Memo1.Lines.Add('Entry retrieved by EntryID:');
Memo1.Lines.Add('  FileName: ' + CkZipEntry__fileName(entry2));
Memo1.Lines.Add('  EntryID: ' + IntToStr(CkZipEntry_getEntryID(entry2)));
Memo1.Lines.Add('');

// The filenames and EntryID values should match.
CkZip_CloseZip(zip);

Memo1.Lines.Add('Done.');

CkZip_Dispose(zip);
CkZipEntry_Dispose(entry);
CkZipEntry_Dispose(entry2);

end;