Delphi Versions

I started developing with Delphi 2, I moved to Delphi 5 at some point, and I am struggling with Delphi 6. Of the 3, Delphi 5 is definitely the best.

TPageControl | Built-In Help | Built-In Actions | Different Units

TPageControl

Programs that compile perfectly in Delphi 5 have problems when converted to Delphi 6 and then converted back to Delphi 5. For instance, both versions use the TPageControl ... however, the number of published properties is different in the 2 versions.

Specifically, TPageControl.TabIndex

In delphi 5, TabIndex is a protected property of TCustomTabControl. In Delphi 6, it is published (and therefore stored in the *.dfm [Form definition] file).

So,

I opened the program in Delphi 6
I made a minor change
I saved the form and Delphi 6 added TabIndex to the *.dfm file
I opened the form in Delphi 5 and got an error
Error reading PageControl1.TabIndex: Property does not exist. Ignore the error and continue? NOTE: Ignoring the error may cause components to be deleted or property values to be lost.

Built-In Help

Delphi 5 - super
Delphi 6 - What happend??

Windows SDK:

In Delphi 5, help on the Windows commands is provided via Help / Windows SDK
This is not available with Delphi 6, instead you must manually navigate to

  C:\Program Files\Common Files\Borland Shared\MSHelp

Since I use this all the time, this is a major issue

Component Help

This is the help you get when you click a property in the Object Inspector and press F1

In Delphi 5, it works perfectly

In Delphi 6, it is totally unreliable

Built-In Actions

Actions are one of the reasons that Delphi is a super language. In Delphi 5, only a few Built-In Actions were provided. Delphi 6 adds a bunch more ... if only they worked.

Specifically, two actions (TSearchFind and TSearchReplace) are based on TSearchAction. The critical line is

P := SearchBuf(Buffer, Size, EditControl.SelStart, EditControl.SelLength,
             SearchString, SearchOptions);

Unfortunately, SearchBuf does not locate a match if the target pattern of characters occurs at the beginning of the string being searched - Fixed in Delphi 6 Update Pack.

Neither version has enough documentation on these - see Pre-Defined action classes for about one line per action.

Improved Actions

Delphi 6 adds a new Action manager that simplifies building menus and toolbars. I haven't used this yet because my code has to also compile under version 5.

Different Units

Units are included via a uses clause. In addition to the new capabilities added to Delphi 6, some Delphi 6 capabilities require including different units than Delphi 5 used. Unfortunately, if you want code to compile in both versions, you now have to include conditional compiler directives to automatically swap units.

For instance, Variants are built into the Delphi 5 compiler and no units need to be included - in Delphi 6, you must include the Variants unit. This example will work in both compilers.

{$IFDEF VER130}       // Delphi 5
  {$DEFINE mc_LE_D5}  // Less than or equal to Delphi 5 
                      // I use "mc" to help avoid conflicts
{$ENDIF}

{$IFNDEF mc_LE_D5}
uses
  Variants; // Delphi 6 and above only 
{$ENDIF}

Some other differences

Delphi 5 and 6 use different units to define property editors
For web servers, Delphi 6 requires HTTPProd