Command Line Parser Library - Boolean Parameter

Question

I try to pass a boolean parameter to a console application and process the value with the Command Line Parser Library.

[Option('c', "closeWindow", Required = true, HelpText = "Close the window.")]
public bool CloseWindow { get; set; }

I tried to pass the parameter as

-c false
-c False
-c "false"
-...

There are no differences, on each try I get "true" as value.

Can anyone tell me how I have to pass the parameter to get the boolean false value?

To avoid possible asks, there is a string option which is passed correctly:

[Option('s', "system", Required = true, HelpText = "Any help text")]
public string System { get; set; }

I would have thought Boolean parameters are present or not present. They don't require and argument - no idea how that works with `Required = true` — James, Mar 08 '16 at 17:26

arne.z · Accepted Answer · 2016-03-08T17:41:21.557

45

You don't need to add True or False. Using -c will evaluate to True. Not using it will evaluate to False. Somewhere in the documentation there is an example with -v for verbose output. But I can't find it right now. I guess Required=true is not necessary for Boolean options.

edited Mar 08 '16 at 17:41

answered Mar 08 '16 at 17:26

arne.z

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You are right, passing -c is evaluated as true if -c is not passed i get false. But what is if I want to use the "Required" option? – Sebastian S. Mar 08 '16 at 17:38
I think the library is not intended to use it this way, but you could make your option a string and then match the string to evaluate your Boolean. You can probably do that in the getter function of your option. – arne.z Mar 08 '16 at 17:44
16

How about if default is 'True', how would this parameter make sense? Not specifying it means 'True' because of the default, specifying it means 'True', because is specified. – Kosmo Jun 27 '18 at 16:41
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IMHO, that looks like a design fault – momo Mar 12 '19 at 16:03
1

@momo, that's because it is. – A.R. Jan 26 '22 at 16:13

score 44 · Answer 2 · edited Mar 16 '23 at 19:42

44

bool? behaves the way you want

with:

[Option('c', "closeWindow", Required = true, HelpText = "Close the window.")]
public bool? CloseWindow { get; set; }

the result will be:

-c false // -> false
-c true  // -> true
-c       // -> error
         // -> error if Required = true, null otherwise

edited Mar 16 '23 at 19:42

Uwe Keim

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answered Dec 19 '19 at 15:10

klev

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score 0 · Answer 3 · answered Jan 12 '22 at 14:48

0

Here is a work-around to consider:

Change the names of the options so false is always the default. If you want "close window" to be the default, then the name of the option becomes -w "keepWindowOpen".

answered Jan 12 '22 at 14:48

James Lawruk

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Command Line Parser Library - Boolean Parameter

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