Mastering Visual Studio .NET 1002003 [Electronic resources] نسخه متنی

F.2 Generic Settings

Two categories of settingsGeneral and Tabsare present
in all languages.

The General item that appears under all of the languages is different from the General tab that appears directly under the Text Editor folder, despite having the same name.

Visual Studio .NET allows you to specify these settings on a
per-language basis. However, if you want to use the same settings for
these two categories in all languages, you can do so using the Text
Editor All Languages folder.

The General and Tabs categories contain settings for common editor
services. However, some languages do not use all of these services.
For example, the General setting lets you configure IntelliSense, but
the Plain Text "language" (used for
editing .txt files) cannot support this feature.
In such cases, the relevant checkboxes will be grayed out.

F.2.1 General

The configuration panel for the General settings presents three
groups of settings: Statement Completion, Settings, and Display.

Here is a summary of the General settings:

Autolist Members

IntelliSense will automatically show members of a type during code
editing.

Hide Advanced Members

IntelliSense will hide advanced members of a type.

Parameter Information

IntelliSense will automatically show parameter information for
function calls.

Enable Virtual Space

The insertion point can be placed anywhere in the editor window
(whitespace padding will be inserted when necessary).

Word Wrap

Long lines of code will wrap within the text editor window.

Line Numbers

Line numbers will appear on the lefthand margin of the text editor.

Enable Single-click URL Navigation

URLs can be followed using a single-click.

Navigation Bar

A class/member navigation bar will appear at the top of the text
editor window.

The first group, Statement Completion, contains three
IntelliSense-related settings. The first
(Autolist Members) determines whether
Visual Studio .NET will display a pop-up list of members in
appropriate scopes. With this option enabled, a member list will
automatically appear in C# and VB.NET projects if you type a variable
or class name followed by a period (.). (In C++ it
will appear after typing in either a period, the
operator, or the :: operator, depending on the
type of identifier.)

The second IntelliSense-related setting is Hide
Advanced Members. This determines which members will be displayed on
the member list. If this is enabled, certain items will be hidden
when the member list is displayed. It is up to each individual
language service to decide what constitutes an
"advanced" member to be hidden.
VB.NET is the most interesting language since it hides the most.
Consider the following class definition:

Public Class TestHidden
Public Sub Foo(  )
End Sub
Private Sub Quux(  )
End Sub
End Class

When Hide Advanced Members is turned on, the member list (see Figure F-1) shows only the Foo member
function and the GetType function, which is
defined by the base type (System.Object). If Hide
Advanced Members is turned off, we will also see all of the functions
that are inherited from the base class, as Figure F-2 shows. Note that in both cases, only the
public members are shownthe member list will show only members
that are in scope. (The private member Quux would
have been visible if we had tried to display the member list from
inside the TestHidden class itself.)

Figure F-1. Hide Advanced Members on

Figure F-2. Hide Advanced Members off

Although VB.NET makes its own decisions about which members of
intrinsic types such as System.Object are
advanced, we can influence its decisions with our own types. The .NET
Framework Class Library defines a custom attribute called
EditorBrowsable, which is defined in the
System.ComponentModel namespace. We can use this
to indicate that particular members of our classes are advanced. We
can modify our TestHidden example to use this:

Imports System.ComponentModel
Public Class TestHidden
<EditorBrowsable(EditorBrowsableState.Advanced)> _
Public Sub Foo(  )
End Sub
Private Sub Quux(  )
End Sub
End Class

This marks the Foo method as being advanced.
VB.NET will no longer display this item in member lists if the Hide
Advanced Members option is selected.

VB.NET and C# are the only languages that support the Hide Advanced
Members settingit is grayed out for all other languages.
VB.NET has it turned on by default, while in C# it is turned off by
default. Even if you turn it on for C#, the behavior you get is not
quite the same as for VB.NET. C# considers a member to be advanced
only if it has had the relevant EditorBrowsable
attribute applied, so unlike VB.NET it will not hide members of the
System.Object class. Also, C# honors the
EditorBrowsable attribute only on classes defined
in external componentsit is ignored for classes in the same
project.

Hide Advanced Members can be selected even if Autolist Members is
deselected. This is because even though Autolist might be turned off,
the list of members of a type can still be displayed by pressing
Ctrl-J or Ctrl-Space.

The third IntelliSense-related setting is
Parameter Information. When this option
is selected, the parameter information for a particular function is
automatically displayed when the function delimiter (in most cases
the left parenthesis) has been typed in. The parameter information
can be displayed at any time by using the Ctrl-Shift-spacebar
shortcut while the cursor is inside a parameter list, regardless of
whether this setting is enabled.

The second group of options in the General category is under the
heading Settings. It contains two settings that affect the way you
see and type text. The first, Enable Virtual Space,
is off by default. If you turn this setting on, you will be able to
place the cursor beyond the end of the line of code you are typing
on. The space between the end of the line of code and the new
placement of the cursor is automatically filled in with whitespace.
This is similar to Microsoft Word's click-and-type
feature.

The second option under Settings turns word wrap on or off. (Again,
it is off by default.) When this option is enabled, any text that
would appear beyond the righthand side of the text editor window is
automatically placed on the next line. VS.NET does not insert
line-feed characters in the text to achieve thisthis option
merely changes how overly long lines are displayed.

The General category's third group of options is
labeled Display. (It's not entirely clear what the
distinction between Settings and Display is supposed to be. Word wrap
is a display feature, despite appearing in Settings, and some of the
items in Display modify the editor's behavior!) The
first item, Line Numbers, determines whether numbers
are shown on the lefthand side of the text editor pane (between the
indicator margin and the selection margin). If
Enable Single-click URL Navigation is
on, a single-click on a URL in the text editor will follow the URL.
If disabled, you have to right-click on the URL and select Navigate
to URL. (The text editor supports this behavior for any text that
looks plausible as a URL, regardless of context.) The last option,
Navigation Bar, determines whether a
class and member navigation bar is displayed at the top of the text
editor. The navigation bar is described in Chapter 2.

F.2.2 Tabs

The second category of text editor
settings available in all languages is the Tabs category. Here is a
summary of the Tabs settings:

Indenting

Controls whether and how automatic indenting is applied to source code

Tab Size

The number of spaces between each tab stop

Indent Size

The number of spaces inserted when you press the Tab key or when
VS.NET indents your code

Insert Spaces/Keep Tabs

Determines whether VS.NET will insert tab characters when it
can

The first setting, Indenting, controls the behavior of the editor
when you press the Enter key. It can be set to None, Block, or Smart.
When set to None, the text editor never indents automatically. When
set to Block, the text editor indents new lines by the same amount as
the preceding line.

The most helpful indentation setting is Smart. This setting uses the
current language service to provide context-sensitive indentation.
For example, in a C# file, when you press Enter after an open brace
({), the language service tells the text editor to
indent the new line by more than the preceding one. And when you type
a closing brace, the editor (under the guidance of the C# Language
Service) locates the line containing the corresponding opening brace
and indents the closing brace by the same amount as the opening one.
(It also reformats all of the code in between to fix its indentation
if necessary.)

The next pair of settings (which are under the Tabs heading) allows
you to control tab sizes. The first value, Tab Size determines the
number of spaces between tab stops when a tab character is used.
(Remember that a tab character does not insert a fixed number of
spaces; it merely advances to the next tab stop.) By default, tab
stops are 4 characters apart.

The default of 4 is an incongruous choice, since Windows itself favors 8-character tab stops, as do many other platforms. However, many years ago, the Visual C++ team decided to use 4-character tab stops in its editor, on the grounds that this is a much more useful width for tab stops than 8 characters. Unfortunately, although 4-character tabs may well be more useful to software developers than 8-character tabs, most other software in Windows carries on using 8-character tab stops. This means that if you open text files containing tab characters in most other editors, they look completely different from how Visual Studio .NET shows them. (In fact, not even all of the development tools that ship with VS.NET follow suitWinDiff.exe uses the more common 8-character convention.) Changing this setting to 8 is not recommended either. Although this would be more consistent with other Windows software, a considerable amount of the source code that ships with VS.NET is formatted presuming 4-character tab stops, as is much of the wizard-generated code. This would all look wrong if you changed this setting to 8. The only way to guarantee consistent display of your files in VS.NET and other tools is not to use tabs at all. (Fortunately, this is easyuse the Insert Spaces option described later.)

The second text box in the Tabs section of the Tabs category is
Indent Size. This determines the spacing that Visual Studio .NET will
use when you press the Tab key or when smart indenting decides to
insert a tab in some code for you. (Again, the default is 4.) This
setting is entirely independent of Tab Size. Tab Size controls how
tab characters will be displayed; Indent Size controls how Visual
Studio .NET will format your code. (Just because your system may be
configured to display tabs as 4 characters wide, you are not required
to format your code in 4-character columns.)

Visual Studio .NET will not necessarily insert a tab character when
you press the Tab key or when it performs automatic indentation. For
one thing, you may have chosen an Indent Size that is incompatible
with the Tab Size. (For example, if you like to format your code with
3-space indentation, this style does not line up very well with
either 4-character or 8-character tab stops.) But when use of tab
characters is an option, VS.NET will insert them if you want it to.

The wizards ignore the tab settings. They always generate code with tab characters, because the code is based on a template file that contains tab characters. See Chapter 9 for details on how to add your own tab-free templates to VS.NET.

If you choose the Insert Spaces radio button, Visual Studio .NET will
never generate any tab characters. All indentation will be done
entirely with spaces. This has the advantage that your files will
look the same in any text editor. It has the slight disadvantage of
making your files larger. The alternative is to select Keep Tabs.
This will cause Visual Studio .NET to generate tab characters
whenever possible. If your Indent Size setting is not an exactly
multiple of your Tab Size setting, VS.NET will use tab characters
when possible and fall back to spaces otherwise. For example, suppose
you use 3-space indentation with 4-character tab stops. If your
current indentation level is 15 columns, VS.NET will insert 3 tabs to
form the first 12 columns, followed by 3 spaces to make it up to 15.

We recommend that you choose the Insert Spaces setting. This is the only way to guarantee that the files you create with VS.NET will look the same in all text editors. The increase in file size is nominal and is a small price to pay for guaranteed consistency.