ch11.htm

delphi自学的好教材！特别适合刚刚起步学习delphi的人员！同样对使用者具有参考价值！

<BLOCKQUOTE>
	<P>
<HR>
<strong>NOTE:</strong> A common practice with commercial applications is to create hidden
	windows to accomplish a specific task in the application. Hidden windows just show
	the text (hidden) after the module name. Because the window is hidden, there is no
	size and position information, nor is there any window text.
<HR>


</BLOCKQUOTE>

<P>The Window Tree is hierarchical. At the top of the tree is the Windows Desktop.
Under that are any windows created as children of the desktop. An executable file,
for example, appears under the desktop node. A given window can have other child
windows under it. Lines connect the parents, their children, and any siblings.</P>
<P>You will notice back in Figure 11.8 that a diamond appears to the left of each
item in the Tree Window. If a window has children, the diamond contains either a
plus sign or a minus sign. If the diamond has a plus sign, it means the node is contracted
and can be expanded to reveal the child windows. If the node has a minus sign, the
plus is already expanded. You can expand or contract a node by clicking anywhere
to the left of the item. Blank diamonds indicate a window without children.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>NOTE:</strong> If a particular window is enabled in the Window Tree, the diamond
	next to the item flashes whenever the window receives a message from Windows. 
<HR>


</BLOCKQUOTE>

<H3><A NAME="Heading13"></A>The Message Trace Window</H3>
<P>The Message Trace window shows the individual messages as they are generated by
Windows. A typical Message Trace item looks like this:</P>
<P>
<PRE>000684:00000854 {TMemo} WM_KEYDOWN Dispatched 48h 72d VK_H Scan 23h Down
</PRE>
<P>It doesn't pay to analyze this in detail because the exact details vary so much
from message to message. In this case, a memo component received a WM_KEYDOWN message
with a parameter of VK_H. In other words, the user pressed the <I>h</I> key with
the cursor in a memo component. As you can see, some of the information shown in
a Message Trace item also appears in the Window Tree. For example, the window handle
is displayed as well as the class name.</P>
<P>You begin the message trace by choosing the Start! item in the main menu. The
messages will begin appearing in the Message Trace window as they are received by
the window or windows you have selected. To stop the message trace, choose the Stop!
item in the main menu.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>NOTE:</strong> The Stop! and Start! items in the main menu occupy the same place
	on the menu bar. If the message trace is off, the menu item reads Start! If the trace
	is running, the menu item reads Stop!.
<HR>


</BLOCKQUOTE>

<P>Messages scroll through the Message Trace window as they are received. You can
always stop the message trace and scroll back through the list to view any messages
that have scrolled out of view. Another option is to send the message output to a
log file. WinSight options are discussed later in the section &quot;Message Trace
Options.&quot;</P>
<P>
<H3><A NAME="Heading14"></A>Spying on a Window</H3>
<P>WinSight enables you to view all messages sent to all windows or messages sent
to a particular window. To view all messages, choose Messages|All Windows from the
main menu. Although you can choose to view all messages sent to all windows, it isn't
usually productive. There are so many messages flying around that it is hard to pick
out the specific ones you are looking for.</P>
<P>A better method is to select a specific window and then watch the messages for
just that window. That will keep the clutter in the Message Trace window to a manageable
level. To view the messages for a specific window, locate the window in the Message
Tree and click on it to select it. Now choose Messages|Selected Windows from the
main menu. Choose Start!, and any messages sent to the selected window will show
up in the Message Trace window.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>TIP:</strong> It's best to have a specific idea of what you are looking for when
	you are using WinSight. Because there are so many messages sent to an individual
	window, the message you are looking for will probably scroll off the screen very
	quickly. To maximize the effectiveness of WinSight, select the window for which you
	want to see messages, start the message trace, manipulate the window any way you
	need to, and turn off the message trace again. 
<HR>


</BLOCKQUOTE>

<H3><A NAME="Heading15"></A>Message Trace Options</H3>
<P>You can control the messages displayed in the Message Trace window via the Message
Trace Options dialog box (see Figure 11.9). You can also change the way the message
is displayed. To view the Message Trace Options dialog box, choose Messages|Options
from the main menu.</P>

<P><BR>
<A HREF="javascript:popUp('28671109.gif')"><B>FIGURE 11.9.</B></A> <I>The Message
Trace Options dialog box.</I></P>

<P><BR>
The section entitled Messages to Trace comprises the bulk of this dialog box. This
section shows several message groups on the left and a list box displaying all Windows
messages on the right. As you select or deselect message groups, the corresponding
messages will be selected or deselected in the list box.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>NOTE:</strong> The list box messages that are all uppercase are the standard Windows
	messages. The lowercase messages are <I>undocumented</I> Windows messages. Undocumented
	messages are messages that are used by Windows, usually for internal use, but are
	not documented in the Windows API help files. 
<HR>


</BLOCKQUOTE>

<P>When the All Messages option is checked, WinSight will trace all Windows messages.
To further specify your messages and thus to reduce clutter in the Message Trace
window, you can elect to view only certain groups of messages. If, for example, you
want to view only mouse messages, you can turn off the All Messages check box and
turn on the Mouse check box. To further specify, you can turn off all options and
then choose a specific message from the list box on the right of the dialog box.
For example, if you want to see only the WM_LBUTTONDOWN message, you can turn off
all options and then select just the WM_LBUTTONDOWN message from the list box. Only
the WM_LBUTTONDOWN messages will be reported in the Message Trace window.</P>
<P>Another group of options on the Message Trace Options dialog box controls how
the messages are displayed in the Message Trace window. The Interpret Values option
tells WinSight to break down each message's parameters into a more readable format.
For example, given a WM_KEYDOWN message, would you rather see</P>
<P>
<PRE>0000309:00000474 {TMemo} WM_KEYDOWN Dispatched
</PRE>
<P>or</P>
<P>
<PRE>0000309:00000474 {TMemo} WM_KEYDOWN Dispatched 44h 68d VK_D Scan 20h Repeat
</PRE>
<P>Most of the time I opt to see more detail, so I generally leave the Interpret
Values option on.</P>
<P>The Hex Values option tells WinSight to display the values in the Message Trace
window in hexadecimal format. This is useful in some situations but probably not
until you've been programming for a while. The Show Times option is of limited use
because it shows a system time that isn't generally meaningful.</P>
<P>The Log file option enables you to send the message trace output to a file on
disk. When this option is on, the messages are still displayed in the Message Trace
Window. This option is useful when you need a hard copy of the messages being generated.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>TIP:</strong> Creating a log file has another advantage. After you create a log
	file and load it into a text editor, you can use the text editor's Find function
	to search for specific messages or message parameters you want to review.
<HR>
<B></B></P>

</BLOCKQUOTE>

<P>
<H3><A NAME="Heading16"></A>Other WinSight Features</H3>
<P>WinSight has other features that make finding and examining windows easier.</P>
<P>
<H4>Viewing Window Details</H4>
<P>The Detail feature of WinSight shows you all the pertinent details of a particular
window. To view a window's details, select the window in the Window Tree and then
choose Spy|Open Detail from the main menu. You can also double-click the window in
the Message Tree or press Enter on the keyboard. Figure 11.10 shows the details of
Windows Explorer.</P>

<P><BR>
<A HREF="javascript:popUp('28671110.gif')"><B>FIGURE 11.10.</B></A> <I>The WinSight
Detail window.</I></P>

<P><BR>
As you can see, the Detail window shows you a great deal about the window you are
examining (probably more than you want to know!).</P>
<P>
<H4>Follow Focus</H4>
<P>This option enables you to select a window in an application and have that window
become the active window in the Window Tree. The Window Tree usually contains dozens
of windows. It is often difficult to find the window you are looking for, so the
Follow Focus feature really comes in handy.</P>
<P>To use this feature, choose Spy|Follow Focus from the main menu. Next, switch
to the application that contains the window for which you want to view messages and,
if needed, click the specific control within that window that you want to spy on.
WinSight automatically selects the window in the Window Tree. To begin spying on
the window, choose Start! from the main menu.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>TIP:</strong> The Follow Focus option stays on until you turn it off. Unless you
	want to view other windows or controls in your application, you should turn off Follow
	Focus as soon as you locate the window you want to spy on.
<HR>


</BLOCKQUOTE>

<H4>Find Window</H4>
<P>The Find Window feature of WinSight is the opposite of Follow Focus: In the Window
Tree, you locate the window you're searching for and then choose Spy|Find Window
from the main menu. WinSight will place a thick frame around the window and will
flash the frame.</P>
<P>The frame stays around the window until you click the window or choose another
window from the Window Tree. The thick frame is drawn on top of all windows so that
you can find a window even if it's hidden under other windows. A window located with
Find Window doesn't come to the top or gain input focus; it is merely identified
for you.</P>


<BLOCKQUOTE>
	<P>
<HR>
<strong>NOTE:</strong> Find Window cannot find hidden windows or windows that are minimized.
<HR>


</BLOCKQUOTE>

<P>The Find Window mode shuts off as soon as focus leaves the Window Tree. If you
click on another application or anywhere else in WinSight, the Find Window mode will
turn off.</P>
<P>
<H4>Switch To</H4>
<P>The Switch To feature enables you to switch to a particular window in an application.
To switch to a window, just find the window in the Window Tree and then choose Spy|Switch
To from the main menu. The window will come to the top and will have input focus.
If the window is minimized, it will be restored to its previous location. Switch
To has no effect on hidden windows.</P>
<P>It will take time working with WinSight before you understand each message and
its significance. In time, though, you will pick it up.</P>
<P>
<H2><A NAME="Heading17"></A>TDUMP</H2>
<P>TDUMP is a command-line program that outputs the structure of an .exe or .dll
(and other file types as well). By default, the output from TDUMP goes to the console,
but it can be redirected to a text file that you can later examine to obtain information
about the program. TDUMP will tell you about the structure of the file, what DLLs
the program uses, what functions in those DLLs the program calls, and other information.
For example, here is part of the file dump results on a program produced by Delphi:</P>
<P>
<PRE>Portable Executable (PE) File
Header base: 00000200
CPU type                 80386
Flags                    818E [ executable 32bit ]
DLL flags                0000 [ ]
Linker Version           2.19
Time stamp               00000000
O/S Version              1.0
User Version             0.0
Subsystem Version        4.0
Subsystem                0002 [ Windows GUI ]
Object count             00000008
Symbols offset           00000000
Symbols count            00000000
Optional header size     00E0
Magic #                  10B
Code size                0003C000
Init Data size           00009000
Uninit Data size         00001000
...(other information)... 
Imports from OLEAUT32.dll
    SysAllocStringLen
    SysStringLen
    VariantChangeTypeEx
    VariantClear
    VariantCopyInd
Imports from MPR.dll
    WNetGetConnectionA
Imports from USER32.dll