How to use special characters in strings like in C#?

[Carl Mercier]

Hi,

Is it possible to use special characters like \n or \t in a VB.NET
string, just like in C#? My guess is NO, but maybe there's something I
don't know.

If it's not possible, does anybody know of a VB.NET function (somebody
must have coded this already) that will interpret strings containings
those special characters, and handle them the same as in C#?

Thanks!

[Herfried K. Wagner [MVP]]

"David" <df*****@woofix .local.dom> schrieb:

Is it possible to use special characters like \n or \t in a VB.NET
string,
just like in C#? My guess is NO, but maybe there's something I don't
know.

No, that's not supported. It's a rare case that you really need a "\n"
inside a string literal. Instead, use 'ControlChars.N ewLine' which will
contain a platform-specific new-line string.

Is that actually documented someplace, that NewLine will return a
platform-specific string? Does anyone know if mono does this (I've
never used the vb stuff in mono)?

It's not documented for 'Microsoft.Visu alBasic.Control Chars.NewLine'. The
current implementation will return a 'CRLF' sequence. However, it's
documented for 'System.Environ ment.NewLine' ("Gets the newline string
defined for this environment", "The property value is a constant customized
specifically for the current platform"), and I think that this would make
sense for 'ControlChars.N ewLine' too.

I am not sure if 'ControlChars.N ewLine' in mono will return an
environment-specific new-line string, but I would expect it to do so.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Carl Mercier]

Unscape works like a charm! EXACTLY what I was looking for.

Thank you -very- much for this!

Carl
Jay B. Harlow [MVP - Outlook] wrote:

Carl,
| Is it possible to use special characters like \n or \t in a VB.NET
| string, just like in C#?
As the others have pointed out \n & \t are a compile time feature of C#, not
a runtime feature.
It sounds like you want a runtime feature that will convert the C# escape
sequences into valid chars. I don't know how complete it is, RegEx.Unescape
will unescape most if not all of the C# escape sequences.

http://msdn.microsoft.com/library/de...scapetopic.asp
Alternatively I would consider using a RegEx.Replace with a MatchEvaluator
function.

Something like:

Private Shared Function EscapeCharacter s(ByVal match As Match) As String
Select Case match.Value
Case "\b"
Return ControlChars.Ba ck
Case "\t"
Return ControlChars.Ta b
Case "\r"
Return ControlChars.Cr
Case "\v"
Return ControlChars.Ve rticalTab
Case "\f"
Return ControlChars.Fo rmFeed
Case "\n"
Return ControlChars.Lf
Case Else
Return match.Value.Sub string(1)
End Select
End Function

Const pattern As String = "\\."
Static parser As New Regex(pattern, RegexOptions.Co mpiled)

Dim input As String
Dim output As String
input = parser.Replace( input, AddressOf EscapeCharacter s)

The advantage of RegEx.Replace is you have control over how the escape
sequences are defined. For example you could use {Back}, {Tab}, {Cr}, ...
instead.

With effort it should be easy to add support for octal (\040), hex (\x20),
control (\cC), unicode (\u0020) sequences.

Hope this helps
Jay

"Carl Mercier" <no****@nospam. com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..
| Hi,
|
| Is it possible to use special characters like \n or \t in a VB.NET
| string, just like in C#? My guess is NO, but maybe there's something I
| don't know.
|
| If it's not possible, does anybody know of a VB.NET function (somebody
| must have coded this already) that will interpret strings containings
| those special characters, and handle them the same as in C#?
|
| Thanks!

[David]

On 2005-04-23, Herfried K. Wagner [MVP] <hi************ ***@gmx.at> wrote:

"David" <df*****@woofix .local.dom> schrieb:

Is it possible to use special characters like \n or \t in a VB.NET
string,
just like in C#? My guess is NO, but maybe there's something I don't
know.

No, that's not supported. It's a rare case that you really need a "\n"
inside a string literal. Instead, use 'ControlChars.N ewLine' which will
contain a platform-specific new-line string.
Is that actually documented someplace, that NewLine will return a
platform-specific string? Does anyone know if mono does this (I've
never used the vb stuff in mono)?

It's not documented for 'Microsoft.Visu alBasic.Control Chars.NewLine'. The
current implementation will return a 'CRLF' sequence. However, it's
documented for 'System.Environ ment.NewLine' ("Gets the newline string
defined for this environment", "The property value is a constant customized
specifically for the current platform"), and I think that this would make
sense for 'ControlChars.N ewLine' too.

Yeah, Environment.New Line I knew about.
I am not sure if 'ControlChars.N ewLine' in mono will return an
environment-specific new-line string, but I would expect it to do so.

I just checked the mono source to answer my own question, and it returns
CRLF for .NewLine. That makes sense, since doing otherwise would make
NewLine the only platform-independent member of ControlChars.

[David]

On 2005-04-23, Herfried K. Wagner [MVP] <hi************ ***@gmx.at> wrote:

"Crouchie19 98" <cr**********@s pamcop.net> schrieb:

What I tend to do is say:

Dim nl As String = ControlChars.Ne wLine etc. At least then it will shorten
your code quite a lot

Mhm... I prefer a constant:

\\\
Const NL As String = ControlChars.Ne wLine

Isn't that kinda redundant, since NewLine is already a constant? And if
you want something shorter, why not good ol' vbCrLf, which would seem to
be much more recognizable than making up a new abbreviation?

[Cor Ligthert]

Herfried

That is an answer *I* like *better*.

You know what I mean probably

I have to correct my answer: Using a constant is the "best" solution in
this case:

When using a constant, the compiler will be able to perform the
concatenation at compile time, when using a string variable, the
concatenation is done at runtime.

And this one *I* like even *better*

Cor

[Herfried K. Wagner [MVP]]

"David" <df*****@woofix .local.dom> schrieb:

What I tend to do is say:

Dim nl As String = ControlChars.Ne wLine etc. At least then it will
shorten
your code quite a lot

Mhm... I prefer a constant:

\\\
Const NL As String = ControlChars.Ne wLine

Isn't that kinda redundant, since NewLine is already a constant? And if
you want something shorter, why not good ol' vbCrLf, which would seem to
be much more recognizable than making up a new abbreviation?

ACK. The "prefer" in my sentence was related to variable vs. constant only.
I always use 'ControlChars.N ewLine', or I import 'ControlChars' and use the
unqualified 'NewLine'. Note that there is a 'vbNewLine' constant too.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Herfried K. Wagner [MVP]]

"David" <df*****@woofix .local.dom> schrieb:

> Is it possible to use special characters like \n or \t in a VB.NET
> string,
> just like in C#? My guess is NO, but maybe there's something I don't
> know.

No, that's not supported. It's a rare case that you really need a "\n"
inside a string literal. Instead, use 'ControlChars.N ewLine' which
will
contain a platform-specific new-line string.

Is that actually documented someplace, that NewLine will return a
platform-specific string? Does anyone know if mono does this (I've
never used the vb stuff in mono)?

It's not documented for 'Microsoft.Visu alBasic.Control Chars.NewLine'.
The
current implementation will return a 'CRLF' sequence. However, it's
documented for 'System.Environ ment.NewLine' ("Gets the newline string
defined for this environment", "The property value is a constant
customized
specifically for the current platform"), and I think that this would make
sense for 'ControlChars.N ewLine' too.

Yeah, Environment.New Line I knew about.

I am not sure if 'ControlChars.N ewLine' in mono will return an
environment-specific new-line string, but I would expect it to do so.

I just checked the mono source to answer my own question, and it returns
CRLF for .NewLine. That makes sense, since doing otherwise would make
NewLine the only platform-independent member of ControlChars.

I don't think that this is a valid reason for making 'NewLine' not platform
dependent.

I remember that once 'vbNewLine' returned different character sequences on
Windows and on the Macintosh ("Platform-specific newline character; whatever
is appropriate for the platform"). A similar statement can be found in the
VB6/VBA documentation. The VB.NET documentation IMO doesn't explicitly
state that, mainly because VB.NET is not standardized and Microsoft doesn't
provide an implementation for another platform than Windows.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Stephany Young]

For what it's worth:

System.Environm ent,NewLine
Microsoft.Visua lBasic.ControlC hars.CrLf
Microsoft.Visua lBasic.ControlC hars.NewLine
Microsoft.Visua lBasic.Constant s.vbCrLf
Microsoft.Visua lBasic.Constant s.Newline

all return ChrW(13) & ChrW(10)

The IL for them, respectively is:

.method public hidebysig specialname static string get_NewLine() cil
managed
{
// Code Size: 6 byte(s)
.maxstack 8
L_0000: ldstr "\r\n"
L_0005: ret
}

.field public static literal string CrLf = string("\r\n")

.field public static literal string NewLine = string("\r\n")

.field public static literal string vbCrLf = string("\r\n")

.field public static literal string vbNewLine = string("\r\n")

"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:us******** ******@tk2msftn gp13.phx.gbl...

"David" <df*****@woofix .local.dom> schrieb:

>> Is it possible to use special characters like \n or \t in a VB.NET
>> string,
>> just like in C#? My guess is NO, but maybe there's something I don't
>> know.
>
> No, that's not supported. It's a rare case that you really need a
> "\n"
> inside a string literal. Instead, use 'ControlChars.N ewLine' which
> will
> contain a platform-specific new-line string.

Is that actually documented someplace, that NewLine will return a
platform-specific string? Does anyone know if mono does this (I've
never used the vb stuff in mono)?

It's not documented for 'Microsoft.Visu alBasic.Control Chars.NewLine'.
The
current implementation will return a 'CRLF' sequence. However, it's
documented for 'System.Environ ment.NewLine' ("Gets the newline string
defined for this environment", "The property value is a constant
customized
specifically for the current platform"), and I think that this would
make
sense for 'ControlChars.N ewLine' too.

Yeah, Environment.New Line I knew about.

I am not sure if 'ControlChars.N ewLine' in mono will return an
environment-specific new-line string, but I would expect it to do so.

I just checked the mono source to answer my own question, and it returns
CRLF for .NewLine. That makes sense, since doing otherwise would make
NewLine the only platform-independent member of ControlChars.

I don't think that this is a valid reason for making 'NewLine' not
platform dependent.

I remember that once 'vbNewLine' returned different character sequences on
Windows and on the Macintosh ("Platform-specific newline character;
whatever is appropriate for the platform"). A similar statement can be
found in the VB6/VBA documentation. The VB.NET documentation IMO doesn't
explicitly state that, mainly because VB.NET is not standardized and
Microsoft doesn't provide an implementation for another platform than
Windows.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>