Example #3: Finding a Resource

To find a Resource we use either the FindEntry or FindEntryIndex methods of TPJResourceFile. The difference is that FindEntry returns the TPJResourceEntry object for the entry (or nil if not found) while FindEntryIndex returns the index of the entry in the Entries property.

Let us assume a Resource file is loaded into the TPJResourceFile variable ResFile. We want to find a RT_HTML Resource named INDEX_HTML. The following code checks if such a Resource exists and displays its data size in a message box, or a message saying the Resource doesn’t exist. This first version of the code uses FindEntry:

// Version using FindEntry
var
  ResFile: TPJResourceFile;
  Entry: TPJResourceEntry;
begin
  ...
  // Assume ResFile contains a loaded Resource file
  ...
  Entry := ResFile.FindEntry(RT_HTML, 'INDEX_HTML', $0809);
  if Assigned(Entry) then
    ShowMessageFmt(
      'Data size for INDEX_HTML is %d',
      [Entry.DataSize]
    )
  else
    ShowMessage('Can''t find Resource');
  ...
  // Don't forget to free ResFile at some stage.
end;

The second version of the code shows how the same Result is obtained with FindEntryIndex:

// Version using FindEntryIdex
var
  ResFile: TPJResourceFile;
  Entry: TPJResourceEntry;
  Idx: Integer;
begin
  ...
  Idx := fResFile.FindEntryIndex(RT_HTML, 'INDEX_HTML');
  if Idx >= 0 then
  begin
    Entry := fResFile.Entries[Idx];
    ShowMessageFmt(
      'Data size for INDEX_HTML is %d', [Entry.DataSize]
    );
  end
  else
    ShowMessage('Can''t find Resource');
  ...
end;

Note that we have used the “short form” of the FindEntry and FindEntryIndex methods above: they find the first Resource with the given type and name, irRespective of language id. The long versions of the methods find a specific Resource type, name and language. For example the following code finds a RT_HTML Resource named INDEX_HTML with a language id of $0809:

// "Full" version of FindEntry
var
  ResFile: TPJResourceFile;
  Entry: TPJResourceEntry;
begin
  ...
  Entry := ResFile.FindEntryIndex(RT_HTML, 'HTMLRes_HTML', $0809);
  if Assigned(Entry) then
    ... etc ...
end;

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Example #3: Finding a Resource