Stringbuilder and concatentaion question

[Joe Fallon]

Is concatentaion inside of a Stringbuilder "evil"?

Which is the preferred syntax below?

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf)
sb.Append("Line 2" & vbCrLf)
sb.Append("Line 3" & vbCrLf)

Syntax #2
Dim sb As New StringBuilder
sb.Append("Line 1")
sb.Append(vbCrL f)
sb.Append("Line 2")
sb.Append(vbCrL f)
sb.Append("Line 3")
sb.Append(vbCrL f)

--
Joe Fallon

[Herfried K. Wagner [MVP]]

* "Joe Fallon" <jf******@nospa mtwcny.rr.com> scripsit:

Is concatentaion inside of a Stringbuilder "evil"?

Which is the preferred syntax below?

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf)
sb.Append("Line 2" & vbCrLf)
sb.Append("Line 3" & vbCrLf)

Syntax #2
Dim sb As New StringBuilder
sb.Append("Line 1")
sb.Append(vbCrL f)
sb.Append("Line 2")
sb.Append(vbCrL f)
sb.Append("Line 3")
sb.Append(vbCrL f)

I vote for #1, because the compiler will remove the concatenation and
store the concatenated string literal instead ("Line 1\r\n"). So, #1
will have better performance because there are fewer method calls.

--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
<URL:http://dotnet.mvps.org/dotnet/faqs/>

[Dick Grier]

You can do concatenation inside the argument that you pass to StringBuilder.

--
Richard Grier (Microsoft Visual Basic MVP)

See www.hardandsoftware.net for contact information.

Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
Edition ISBN 1-890422-27-4 (391 pages) published February 2002.

[Joe Fallon]

Herfried,
Excellent.
I was hoping for an answer like that!
Thanks.
--
Joe Fallon
"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:OP******** ******@TK2MSFTN GP12.phx.gbl...

* "Joe Fallon" <jf******@nospa mtwcny.rr.com> scripsit:

Is concatentaion inside of a Stringbuilder "evil"?

Which is the preferred syntax below?

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf)
sb.Append("Line 2" & vbCrLf)
sb.Append("Line 3" & vbCrLf)

Syntax #2
Dim sb As New StringBuilder
sb.Append("Line 1")
sb.Append(vbCrL f)
sb.Append("Line 2")
sb.Append(vbCrL f)
sb.Append("Line 3")
sb.Append(vbCrL f)

I vote for #1, because the compiler will remove the concatenation and
store the concatenated string literal instead ("Line 1\r\n"). So, #1
will have better performance because there are fewer method calls.

--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
<URL:http://dotnet.mvps.org/dotnet/faqs/>

[Jay B. Harlow [MVP - Outlook]]

Joe,
I prefer #2, as I am not creating a temporary string for each append.

However in your specific example, ("Line 1" & vbCrLf) is a constant and will
not create a temporary string (the compiler will concat the strings at
compile time). Which also means in your specific example you should do a
single Append instead of 3 appends!

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf & "Line 2" & vbCrLf & "Line 3" & vbCrLf)
Where as the follow will create temporary strings, possibly negating the
"benefit" of using the StringBuilder in the first place:

Public Sub GetString(line1 As String, line2 As String, line3 As String)
Dim sb As New StringBuilder
sb.Append(line1 & vbCrLf)
sb.Append(line2 & vbCrLf)
sb.Append(line3 & vbCrLf)
End Sub

Also without a Loop or a significant number of concatenations, I would
consider if I really needed to StringBuilder or not...

For example, if I only had the 3 variables, I would consider using
String.Format instead or even String.Concat.

Public Sub GetString(line1 As String, line2 As String, line3 As String)
Const format As String = "{0}" & vbCrLf & "{1}" & vbCrLf & "{2}"
Dim s As String = String.Format(f ormat, line1, line2, line3)
End Sub

The following article discusses when to use multiple Appends with the
StringBuilder:

http://msdn.microsoft.com/architectu...l/scalenet.asp

Hope this helps
Jay

"Joe Fallon" <jf******@nospa mtwcny.rr.com> wrote in message
news:eY******** ******@TK2MSFTN GP10.phx.gbl... Is concatentaion inside of a Stringbuilder "evil"?

Which is the preferred syntax below?

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf)
sb.Append("Line 2" & vbCrLf)
sb.Append("Line 3" & vbCrLf)

Syntax #2
Dim sb As New StringBuilder
sb.Append("Line 1")
sb.Append(vbCrL f)
sb.Append("Line 2")
sb.Append(vbCrL f)
sb.Append("Line 3")
sb.Append(vbCrL f)

--
Joe Fallon

[Cor Ligthert]

Hi Joe,

You can choose for #1, however #2 is faster.

(Execpt of course that you want to do as what Herfried says and use the
Stringbuilder to make this constant Dim myconst as String = "Line1" &
VbCrlF & "Line2" & VbCrlF & "Line3" & VbCrlF, than is this faster, while
using the SB the endresult is no constant)

I assume that Line1 and Line2 are in normal live Strings and no constants.
(I tested it a short while ago the test should be in this newsgroup)

Cor

Is concatentaion inside of a Stringbuilder "evil"?

Which is the preferred syntax below?

Syntax #1
Dim sb As New StringBuilder
sb.Append("Line 1" & vbCrLf)
sb.Append("Line 2" & vbCrLf)
sb.Append("Line 3" & vbCrLf)

Syntax #2
Dim sb As New StringBuilder
sb.Append("Line 1")
sb.Append(vbCrL f)
sb.Append("Line 2")
sb.Append(vbCrL f)
sb.Append("Line 3")
sb.Append(vbCrL f)

--
Joe Fallon

[Cor Ligthert]

Hi Jay,

I did not copy it I was sending it when I saw it . However that you would
not think of me, I know.

:-)

Cor

[Jay B. Harlow [MVP - Outlook]]

Cor,
Huh?

Don't worry, I think of you.

Or maybe you should worry that I think of you. ;-)

Jay

"Cor Ligthert" <no**********@p lanet.nl> wrote in message
news:Ou******** ******@tk2msftn gp13.phx.gbl...

Hi Jay,

I did not copy it I was sending it when I saw it . However that you would
not think of me, I know.

:-)

Cor

[Herfried K. Wagner [MVP]]

* "Cor Ligthert" <no**********@p lanet.nl> scripsit:

You can choose for #1, however #2 is faster.
No!
(Execpt of course that you want to do as what Herfried says and use the
Stringbuilder to make this constant Dim myconst as String = "Line1" &
VbCrlF & "Line2" & VbCrlF & "Line3" & VbCrlF, than is this faster, while
using the SB the endresult is no constant)

No, I didn't say that. The compiler determines that '"Line2" & vbCrLf'
/is/ one constant and stores it as "Line2\r\n" in the binary.

--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
<URL:http://dotnet.mvps.org/dotnet/faqs/>

[Cor Ligthert]

> * "Cor Ligthert" <no**********@p lanet.nl> scripsit:

You can choose for #1, however #2 is faster.

No!

Yes

(When it are not *constants* Google this newsgroup than you find probably a
test I made).

Cor