Rewrite this array manipulation using a lambda function?

Question

I have this routine which alters all elements within an array...

    for (int i = 0; i < sOutputFields.GetUpperBound(0); i ++)
    {
        sOutputFields[i] = clsSQLInterface.escapeIncoming(sOutputFields[i]);
    }

sOutputFields is a one dimensional string array. escapeIncoming() is a function which returns a string.

I thought this could be re-written thus..

    sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el));

..but this appears to do nothing (though does not throw an exception). So I tried..

    sOutputFields = 
       (string[])sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el));

..but I get this exception at execution time..

"Unable to cast object of type 'WhereSelectArrayIterator`2[System.String,System.String]' to type 'System.String[]'."

how to fix?

Query results are immutable, and => is not a assigment operator. — asawyer
– asawyer, Commented Dec 8, 2010 at 14:45
Your LINQ code does not rewrite, rather it creates a new collection — Max
– Max, Commented Dec 8, 2010 at 14:46

CodeMonkey1313 · Accepted Answer · 2010-12-08 14:45:13Z

3

A Select doesn't return an object that can be explicitly cast to an array. You'd need to do sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el)).ToArray<string>() in your assignment.

answered Dec 8, 2010 at 14:45

CodeMonkey1313

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Comments

Jeff Paquette · Accepted Answer · 2010-12-08 14:49:04Z

1

The return type is an IEnumerable, you need to convert to an array:

sOutputFields = sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el)).ToArray();

answered Dec 8, 2010 at 14:49

Jeff Paquette

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1 Comment

El Ronnoco Over a year ago

Thanks :) I see the ToArray<string>() is not required, just ToArray(). Why is that?

Doggett · Accepted Answer · 2010-12-08 14:45:23Z

1

use:

sOutputFields = sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el)).ToArray();

answered Dec 8, 2010 at 14:45

Doggett

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BFree · Accepted Answer · 2010-12-08 14:46:05Z

0

sOutputFields = sOutputFields.Select(el => clsSQLInterface.escapeIncoming(el)).ToArray();

answered Dec 8, 2010 at 14:46

BFree

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