Delphi Tips and Source Code
Conference Papers and Presentations:
Quick Tips on This Page:
- The Repository lets you save forms and projects. Items can
also be marked as the default for the new form or project menu
items. In a team environment, a shared repository can help
achieve a common look and feel throughout your application.
- For faster programming, changing colors in the IDE can really
help to highlight your syntax and pinpoint coding errors more
quickly. You can change colors for keywords, strings, numbers,
punctuation, comments, etc. to help them stand out from the rest
of the code. Colors are a personal choice, but here's a quick
To change the color settings, choose
Options|Environment|Editor Colors in Delphi 1.0 or
Tools|Options|Colors in Delphi 2.0.
- Editing can also be tailored with the Editor Options tab page.
The most useful settings I've found are the following:
especially find text at cursor, the block indent and tab stop
settings. Note with block indent you can also highlight a block
in the code editor and use CTRL-K-I to indent it or CTRL-K-U to
unindent. These keys save a heap of time typing.
- On the subject of editor keystrokes, there are other useful
shortcuts to explore. If you're like me, it's easy to overlook
them for the most part. Steven Jatnieks logged this great tip on
the delphi-talk mailing list: "Delphi has macros. Press
CTRL-SHFT-R to start/stop recording and CTRL-SHFT-P to play the
- Optimize the component palette when designing. If you have a
lot of components installed, you need all the space you can get.
Drag the palette area over the top of the speedbuttons to make
more visible space. You can customize the speedbuttons using the
right mouse button - get rid of the ones you never use to free
up space for the palette.
- Palette pages are also fully customizable. It really can save
time to reorganize the palette into the components you use most
frequently. Use Options|Environment|Palette to get to the
palette editor, then add, delete or reorder pages and
components. You can include the same component on more than one
page, by dragging the component from the [Library] page to a new
- Use the desktops feature in Delphi 5 and up to save frequently
used window configurations for coding and debugging.
This example creates a handy button component that can be used to
automatically create and show forms. It uses properties and events
to set the form name and to show the form modally.
We're essentially using the same approach that Delphi uses in the
Application.CreateForm method. If you have the VCL source you might
want to check it out.
To dynamically create an object using a text string of its class
name, you need to first obtain an object-type reference. This can be
done using the FindClass or GetClass functions. These return a
TPersistentClass type. To create forms on the fly, you need to
recast this as a TFormClass.
Once you have this class reference you can use
Application.CreateForm or the Create method to create a new object,
There is one catch to using FindClass. Before your class can be
found it needs to be registered with Delphi, otherwise you get a
"Class ... not found" error. The best place to register
the class is in the unit that defines the class. Include the
following code in the initialization section at the end of the
For a button component, we might want to modify this to make the
button the owner of the form. The following extract from our
finished component adds the following code to the button's Click
if FFormName = '' then Exit;
if FForm = nil then
AClass := FindClass('T' + FFormName);
AFormClass := TFormClass(AClass);
FForm := AFormClass.Create(Self);
if FShowModal then
FFormModalResult := FForm.ShowModal
if Assigned(FAfterShow) then FAfterShow(Self);
You can see we've also added some properties and code to show the
form either modal or non-modal, and to execute an event after
showing the form. This event is essential for a modal form where you
want to do something after the form is hidden or destroyed.
The full component source includes
additional runtime properties and methods to access the form.
A common method of saving form properties such as position and
size is to write the values to an INI file when destroying the form
and to read them from the file again when creating the form. However
with this approach you need to itemise the properties you want to
save, and this method provides no help for components owned by the
An alternate approach is to use Delphi's own streaming methods.
This allows you to save/restore an entire form to a binary resource
file, including the properties of its owned components. This example
is fairly large, so we've included it as a zip file you can download.
The full source includes a sample project illustrating the use of
If you would like to contribute resources to this page, please
send them to us at firstname.lastname@example.org.