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Argument dependencies sample

This sample shows how to use the argument dependency validators. These validators let you specify that certain arguments must or cannot be used together. It also makes it possible to specify that the user must use one of a set of arguments, something that can't be expressed with regular required arguments.

The validators in question are the RequiresAttribute, the ProhibitsAttribute, and the RequiresAnyAttribute. You can see them in action in ProgramArguments.cs.

This is the usage help output for this sample:

Sample command line application with argument dependencies. The application parses the command line
and prints the results, but otherwise does nothing and none of the arguments are actually used for
anything.

Usage: ArgumentDependencies [[-Path] <FileInfo>] [-Help] [-Ip <IPAddress>] [-Port <Int32>]
   [-Version]

You must use at least one of: -Path, -Ip.

    -Path <FileInfo>
        The path to use.

    -Help [<Boolean>] (-?, -h)
        Displays this help message.

    -Ip <IPAddress>
        The IP address to connect to. Cannot be used with: -Path.

    -Port <Int32>
        The port to connect to. Must be used with: -Ip. Default value: 80.

    -Version [<Boolean>]
        Displays version information.

The validators add their own help messages to the usage help. RequiresAnyAttribute does so before the command list, and the RequiresAttribute and ProhibitsAttribute added text to the descriptions of the arguments they were applied to.

This is, as always fully customizable. You can disable automatic validator help entirely with the UsageWriter.IncludeValidatorsInDescription property (note: this also applies to regular validators like ValidateRangeAttribute), and all the included validators can be included on a case-by-case basis with the IncludeInUsageHelp property on each validator attribute.