string.replace and outofmemoryexception

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pb - 21 Mar 2007 01:38 GMT

can someone suggest a better implementation than my sqlescaptestr function
below?

unfortunately this function throws an outofmemoryexception when i am
inserting multiple rows in a loop (str in such cases can be quite large...
could be upwards of 100K in some cases).

i suppose the loop isn't allowing for the garbage collector to collect... i
could throw a GC in there, but I was hoping for a more memory efficient
function.

Public Shared Function sqlescapestr(ByVal str As String) As String

' replaces ' with ''

str = str.Replace("'", "''")
Return str
End Function

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VJ - 21 Mar 2007 02:53 GMT

always recommended to use StringBuilder (System.Text) class when performing
string operations

VJ

> can someone suggest a better implementation than my sqlescaptestr function
> below?
[quoted text clipped - 15 lines]
> Return str
> End Function

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Jon Skeet [C# MVP] - 21 Mar 2007 08:26 GMT

> always recommended to use StringBuilder (System.Text) class when performing
> string operations

For a simple string replacement like this, it wouldn't help at all.
Using StringBuilder when it isn't useful just makes code less readable.

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VJ - 21 Mar 2007 15:03 GMT

Right.. but looks like there is a for loop (many times) in which this done,
so I reco'd moving to Stringbuilder.

>> always recommended to use StringBuilder (System.Text) class when
>> performing
>> string operations
>
> For a simple string replacement like this, it wouldn't help at all.
> Using StringBuilder when it isn't useful just makes code less readable.

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Jon Skeet [C# MVP] - 21 Mar 2007 20:58 GMT

> Right.. but looks like there is a for loop (many times) in which this done,
> so I reco'd moving to Stringbuilder.

It's being called multiple times, but on different strings - so again,
using a StringBuilder wouldn't help.

StringBuilder is useful when you're doing multiple operations on the
*same* string.

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VJ - 21 Mar 2007 22:24 GMT

Ok Thanks John, did noto see that mulitple strings.. Yes I agree it works
with same string only

VJ

>> Right.. but looks like there is a for loop (many times) in which this
>> done,
[quoted text clipped - 5 lines]
> StringBuilder is useful when you're doing multiple operations on the
> *same* string.

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Jon Skeet [C# MVP] - 21 Mar 2007 08:26 GMT

> can someone suggest a better implementation than my sqlescaptestr
> function below?

I'd suggest avoiding it to start with. Use parameterised queries
instead. That way the driver does whatever is necessary - far more
likely to be accurate.

> unfortunately this function throws an outofmemoryexception when i am
> inserting multiple rows in a loop (str in such cases can be quite large...
> could be upwards of 100K in some cases).

That sounds very unlikely. I think it's more likely that you have a
different problem.

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Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
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Michael Nemtsev - 21 Mar 2007 10:57 GMT

Hello pb,

Try to profile your app to find out what's wrong.
As Jon noted the problem is obviously in other place

---
WBR, Michael Nemtsev [C# MVP].
My blog: http://spaces.live.com/laflour
Team blog: http://devkids.blogspot.com/

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo

p> can someone suggest a better implementation than my sqlescaptestr
p> function below?
p>
p> unfortunately this function throws an outofmemoryexception when i am
p> inserting multiple rows in a loop (str in such cases can be quite
p> large... could be upwards of 100K in some cases).
p>
p> i suppose the loop isn't allowing for the garbage collector to
p> collect... i could throw a GC in there, but I was hoping for a more
p> memory efficient function.
p>
p> Public Shared Function sqlescapestr(ByVal str As String) As
p> String
p>
p> ' replaces ' with ''
p>
p> str = str.Replace("'", "''")
p> Return str
p> End Function

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string.replace and outofmemoryexception

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