The variable 'MyException' is declared but never used

Question

I need to clear this warning :

try
{
    doSomething()
}
catch (AmbiguousMatchException MyException)
{
    doSomethingElse()
}

The complier is telling me :

The variable 'MyException' is declared but never used

How can I fix this.

Gilad Green · Accepted Answer · 2017-08-29 06:47:29Z

163

You can remove it like this:

try
{
    doSomething()
}
catch (AmbiguousMatchException)
{
    doSomethingElse()
}

Use warning disable like this:

try
{
    doSomething()
}
#pragma warning disable 0168
catch (AmbiguousMatchException exception)
#pragma warning restore 0168
{
    doSomethingElse()
}

Other familiar warning disable

#pragma warning disable 0168 // variable declared but not used.
#pragma warning disable 0219 // variable assigned but not used.
#pragma warning disable 0414 // private field assigned but not used.

edited Aug 29, 2017 at 6:47

Gilad Green

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answered Jun 23, 2011 at 14:27

Jalal Said

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7 Comments

Jalal Said Over a year ago

A list of all compiler errors and warnings are available at the MSDN

Ram Over a year ago

The solution given by @fparadis2 is better since not advisable to supress warnings when we can fix it

Jalal Said Over a year ago

@dasariramacharanprasad that was my first suggestion, re-read my answer ;)

Gusdor Over a year ago

solution #2 is not a solution, it is a mask.

Jalal Said Over a year ago

But it is a sharp one isn't it :)

|

Khepri · Accepted Answer · 2011-06-23 14:27:41Z

46

You declare a name for the exception, MyException, but you never do anything with it. Since it's not used, the compiler points it out.

You can simply remove the name.

catch(AmbiguousMatchException)
{
   doSomethingElse();
}

answered Jun 23, 2011 at 14:27

Khepri

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Comments

fparadis2 · Accepted Answer · 2011-06-23 14:28:19Z

33

You can simply write:

catch (AmbiguousMatchException)

and omit the exception name if you won't be using it in the catch clause.

answered Jun 23, 2011 at 14:28

fparadis2

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1 Comment

Ram Over a year ago

+1 since it resolves the warning! not explained in MSDN.

Neil · Accepted Answer · 2011-06-23 15:04:08Z

4

You could write the exception out to a log if you've got one running. Might be useful for tracking down any problems.

Log.Write("AmbiguousMatchException: {0}", MyException.Message);

answered Jun 23, 2011 at 15:04

Neil

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Comments

Brad · Accepted Answer · 2011-06-23 14:28:30Z

3

The trouble is, you aren't using your variable MyException anywhere. It gets declared, but isn't used. This isn't a problem... just the compiler giving you a hint in case you intended to use it.

answered Jun 23, 2011 at 14:28

Brad

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Comments

Ray Chakrit · Accepted Answer · 2018-10-08 18:42:11Z

2

but never used means that you should use it after catch() such as writing its value to console, then this warning message will disappear.

catch (AmbiguousMatchException MyException)
{
    Console.WriteLine(MyException); // use it here
}

answered Oct 8, 2018 at 18:42

Ray Chakrit

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Comments

jmoreno · Accepted Answer · 2023-03-10 15:15:21Z

1

Just ran into this, where the exception was used based upon compiler variables...

Anyway, my solution was:

 _ = MyException;

Picks it up as used, acknowledges that it isn't really being used.

answered Mar 10, 2023 at 15:15

jmoreno

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