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each unit as the unit is being compiled. If there are errors, the compile status
dialog box will report There are errors and will list the number of errors that were
detected as well as any warnings.</P>
<P>Figure 4.9 shows the compile status dialog box after detecting errors. Delphi
compiles your projects so quickly that the compile status dialog box is not generally
necessary. In fact, the compile status dialog box will increase your compile times
because it takes time to display information in the compile status dialog box.</P>
<P><A HREF="javascript:popUp('28670409.gif')"><B>FIGURE 4.9.</B></A><B> </B><I>The
compile status dialog box reporting errors.</I></P>
<P>Regardless of the method chosen to compile the project, if errors are detected,
the Code Editor will come to the top and the message window at the bottom of the
Code Editor will show a list of errors and warnings. The Code Editor highlights the
line where the first error occurred. After a successful syntax check, compile, or
build, you can immediately run the program via the Run button if you choose.</P>
<P>
<H2><A NAME="Heading14"></A>Compiling and Building Other Object Pascal Programs</H2>
<P>Delphi's strength is in its visual programming environment. That environment is
tied directly to VCL and cannot be separated from it. To get the most out of Delphi,
you will most likely be writing applications based on VCL. There are times, however,
when you might want to write other types of applications.</P>
<P>
<P><strong>New Term:</strong> A <I>dynamic link library</I> (DLL) is an external file that
contains code that can be executed from a program or from another DLL.</P>
<PRE></PRE>
<P>Probably the most obvious type of &quot;other&quot; program you might want to
build is a DLL. DLLs might seem a bit like black magic, but they are really not very
complicated: They are simply bits of compiled code that you can call from your application.
After you create the DLL, calling a function contained in a DLL is no different than
calling a function contained in your main program. That's a bit of an oversimplification,
but it is still accurate. DLLs are discussed on Day 19, &quot;Creating and Using
DLLs.&quot;</P>
<P>Another type of application you might write with Delphi is a Win32 console application.</P>
<P><strong>New Term:</strong> A Win32 <I>console application</I> is a 32-bit program that
runs in a DOS box under Windows 95 or Windows NT.</P>
<P>Console applications are useful for small utility programs, servers such as TCP/IP
servers or mail servers, and a whole host of other possibilities. Basically, any
application that does not require a graphical interface is a good candidate for a
console application.</P>
<P>
<H2><A NAME="Heading15"></A>More About Delphi Forms</H2>
<P>Before I continue with the discussion about the Delphi IDE, I need to spend some
time explaining forms. You have seen several forms in action as you have worked through
this book, and on Day 6 you are going to learn all about the Form Designer. Before
you get there, you need some more background information on forms, so I'll cover
that now.</P>
<P>
<H3><A NAME="Heading16"></A>Main Window Forms</H3>
<P>Forms are the main building block of a Delphi application. Every GUI application
has at least one form that serves as the main window. The main window form might
be just a blank window, it might have controls on it, or it might have a bitmap displayed
on it. In a typical Windows program, your main window would have a menu. It might
also have decorations such as a toolbar or a status bar. Just about anything goes
when creating the main window of your application. Each application is unique, and
each has different requirements.</P>
<P>
<H3><A NAME="Heading17"></A>Dialog Box Forms</H3>
<P>Forms are also used for dialog boxes. In fact, to the user there is no difference
between a Delphi form acting as a dialog box and a true dialog box. (By &quot;true
dialog box&quot; I mean a dialog box created the traditional way with a resource
editor and a resource script file. This is how dialog boxes are created in some other
programming environments. Delphi doesn't use traditional dialog boxes, so you will
likely never have to deal with dialog boxes on this level.) Dialog boxes usually
have several traits that distinguish them from ordinary windows:</P>

<UL>
	<LI>Dialog boxes are not usually sizable. They usually perform a specific function,
	and sizing of the dialog box is neither useful nor desirable.
	<P>
	<LI>Dialog boxes almost always have an OK button. Some dialog boxes have a button
	labeled Close that performs the same task. A simple dialog box such as an About dialog
	box typically has only the OK button.
	<P>
	<LI>Dialog boxes can also have a Cancel button and a Help button.
	<P>
	<LI>Dialog boxes typically have only the system close button on the title bar. They
	do not usually have minimize and maximize buttons.
	<P>
	<LI>Some dialog boxes are <I>tabbed dialog boxes</I> that display several tabs from
	which the user can choose. When a tab is clicked, a different page of the dialog
	box is displayed.
	<P>
	<LI>The Tab key can be used to move from one control to the next in most dialog boxes.
</UL>

<P>There are certainly exceptions to every rule. Most dialog boxes have the usual
characteristics, but some dialog boxes perform specialty tasks and as such depart
from the norm in one way or another.</P>
<P>
<H4>Dialogs the Old-Fashioned Way</H4>
<P>In a traditional Windows program (one written in Borland Pascal or using a framework
such as OWL), a dialog box is created with a dialog box editor. In most cases, the
dialog box editor is a visual tool that works somewhat like the Delphi Form Designer.
When the user is done designing the dialog box, the visual representation of the
dialog box is converted into a dialog box definition in a resource script file. To
illustrate, take a look at the dialog box shown in Figure 4.10.</P>
<P><strong>New Term:</strong> A <I>resource script</I> is a text file that is later compiled
into a binary resource file by the resource compiler.</P>
<P><A HREF="javascript:popUp('28670410.gif')"><B>FIGURE 4.10.</B></A><B> </B><I>A
typical About dialog box.</I></P>
<P>Figure 4.10 shows a typical About dialog box. It contains the program name, the
copyright information, and the application's icon. The resource script definition
for the dialog box is shown in Listing 4.1.</P>
<P>
<H4>LISTING 4.1. A DIALOG BOX RESOURCE DEFINITION.</H4>
<PRE> 1: IDD_ABOUT DIALOG 58, 53, 194, 119
 2: STYLE DS_MODALFRAME or WS_POPUP |
 3:   WS_VISIBLE or WS_CAPTION or WS_SYSMENU
 4: CAPTION `About TMMPlayer Example Program'
 5: FONT 8, `MS Sans Serif'
 6: {
 7:  DEFPUSHBUTTON `OK', IDOK, 72, 96, 50, 14
 8:  CTEXT `TMMPlayer Example Program', -1, 48, 22, 128, 8
 9:  CTEXT `Copyright &#169; 1996, by Kent Reisdorph', -1, 32, 47, 136, 8
10:  CTEXT `March 15, 1996', -1, 24, 59, 146, 8
11:  CONTROL `', 99, `button', BS_GROUPBOX |
12:    WS_CHILD or WS_VISIBLE or WS_GROUP, 12, 4, 176, 70
13:  CONTROL 1, 1, `static', SS_ICON |
14:    SS_SUNKEN or WS_CHILD or WS_VISIBLE, 24, 17, 20, 20
</PRE>
<P>15: }</P>
<P>The resource script contains information that Windows uses to build the dialog
box at runtime. This information includes the number and type of controls on the
dialog box, their size, position, text, options, and so on. Of course, the resource
script also includes the same type of information for the actual dialog box.</P>
<P>Some Windows programmers don't use a dialog box editor at all, but prefer to write
the dialog box definition from scratch with a text editor. Although I can't fault
those programmers for creating dialog boxes in that manner, I can say that for most
programmers to take that approach would be, er..., less than 100 percent efficient.
It takes many times longer to create a dialog box in that manner as opposed to the
visual approach.</P>
<P>Usually, all the application's dialog box definitions are contained in a single
resource script file that has a filename extension of .rc. At some point in the program-creation
process, the resource script is compiled into a .res file (the binary resource file),
which then is linked to the .exe by the linker. At runtime the dialog box is displayed
either modally or modelessly depending on the dialog box's intended purpose. When
the dialog box is invoked, Windows loads the dialog box resource from the executable
file, builds the dialog box, and displays it.</P>
<P>
<H4>Dialog Boxes the Delphi Way</H4>
<P>In Delphi, dialog boxes are simply another form. You create a dialog box just
like you do a main window form or any other form. To prevent the dialog box from
being sized, you can change the BorderStyle property to bsDialog or bsSingle. If
you use bsDialog, your dialog box will have only the close box button on the title
bar, which is traditional for dialog boxes. Other than that, you don't have to do
anything special to get a form to behave like a dialog box. All Delphi forms have
tabbing support built in. You can set the tab order by altering the TabOrder property
of the individual controls on the dialog box.</P>
<P><strong>New Term:</strong> A <I>modal</I> dialog box is one that must be dismissed before
the user can continue using the application. The main window of an application is
disabled while this type of dialog box is open. Most dialog boxes are modal.</P>
<P><strong>New Term:</strong> A <I>modeless</I> dialog box is one that allows the user to
continue to work with the application while the dialog box is displayed. The Find
dialog box in some word-processing programs is an example of a modeless dialog box.</P>
<P>A Delphi dialog box (any Delphi form, actually) is modal or modeless depending
on how it is displayed. To execute a modal dialog box, you call the ShowModal method
of TForm. To create a modeless dialog box, you call the Show method.</P>
<P>
<H4>Creating a Dialog Form</H4>
<P>You can now add an About box to the multiple-forms project you created earlier.
If you don't have that project open, choose File | Open Project from the main menu
or click the Open Project button on the toolbar and locate the file. (You should
have saved it with the project name of Multiple.)</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>TIP:</strong> Delphi keeps a list of the files and projects you have used most recently.
	Choose File | Reopen to view the MRU (most recently used) list. The MRU list is divided
	into two parts. The top part shows the projects you have used most recently, and
	the bottom part shows the individual files that you have used most recently. Just
	click on one of the items to reopen that project or file. 
<HR>


</BLOCKQUOTE>

<P>First you'll add a button to the form that displays the About dialog box:</P>

<DL>
	<DT></DT>
	<DD><B>1. </B>Bring the main form into view. Choose the Button component from the
	Component palette and drop a button on the form.
	<P>
	<DT></DT>
	<DD><B>2. </B>Arrange the two buttons that are now on the form to balance the look
	of the form.
	<P>
	<DT></DT>
	<DD><B>3. </B>Change the Name property of the new button to AboutButton and the Caption
	property to About....
	<P>
	<DT></DT>
	<DD><B>4. </B>Double-click the AboutButton you just created on the form. The Code
	Editor is displayed with the cursor placed in the event-handler function. Add this
	line of code at the cursor:
	<P>
</DL>

<PRE>AboutBox.ShowModal;
</PRE>
<P>You haven't actually created the About box yet, but when you do you'll name it
AboutBox, so you know enough to type the code that will display the About box.</P>
<P>Now create the dialog box itself by following these steps:</P>

<DL>
	<DT></DT>
	<DD><B>1. </B>Create a new form (click the New Form button on the toolbar). Size
	the form to the size of a typical About box (roughly the same size as the form named
	SecondForm you created earlier).
	<P>
	<DT></DT>
	<DD><B>2. </B>Change the Name property to AboutBox and change the Caption property
	to About This Program.
	<P>
	<DT></DT>
	<DD><B>3. </B>Locate the BorderStyle property (it's just above Caption) and change
	it to bsDialog.
	<P>
	<DT></DT>
	<DD><B>4. </B>Now add three text labels to the box. Edit the labels so that the About
	box resembles the one shown in Figure 4.11. (You can type any text you want, of course.)
	You can leave the default names Delphi generates for the text labels' Name properties.
	You aren't actually going to do anything with the Name property, so you don't need
	a descriptive name.
	<P>
</DL>

<P><A HREF="javascript:popUp('28670411.gif')"><B>FIGURE 4.11.</B></A><B> </B><I>The
About box with text labels added.</I></P>

<DL>
	<DT><I></I></DT>
	<P>
</DL>



<BLOCKQUOTE>
	<P>
<HR>
<strong>TIP:</strong> The copyright symbol (&quot;) has an ASCII value of 169 in most typefaces.
	To create the copyright symbol, press and hold the Alt key and type the numbers 0169
	on the numeric keypad (be sure Num Lock is on). When you let go of the Alt key, the
	copyright symbol appears. You can insert the ASCII value of any character this way.
	You must type all four numbers, though. For example, the ASCII value of a capital
	A is 65. To insert an A, you have to hold down Alt and type 0065 on the numeric keypad.
	
<HR>


</BLOCKQUOTE>


<DL>
	<DT></DT>
	<P>
</DL>

<P>Next, you can add an icon to the About box:</P>

<DL>
	<DT></DT>
	<DD><B>1. </B>Click the Additional tab on the Component palette and choose the Image
	component. Place the component to the left of the text on the form.
	<P>
	<DT></DT>
	<DD><B>2. </B>Locate the AutoSize property for the Image component and change it
	to True.
	<P>
	<DT></DT>
	<DD><B>3. </B>Locate the Picture property and double-click the Value column. The
	Picture Editor dialog box is displayed.
	<P>
	<DT></DT>