GQL019: Validator method must be valid

	Value
Rule ID	GQL019
Category	Usage
Default severity	Error
Enabled by default	Yes
Code fix provided	No
Introduced in	v8.1

Cause

This rule is triggered when parser method specified by the Validator attribute has invalid signature.

Rule description

The method specified by the Validator attribute must be:

static
return void
have a single argument of type object

Additionally, if the specified method is defined in a different class from where the attribute is applied, the method must be declared as public.

How to fix violations

Fix the method signature to match the required pattern.

Example of a violation

public class TestClass
{
    [Validator(nameof(Validate))]
    public string Hello1 { get; set; }

    [Validator(typeof(Validators), nameof(Validators.ValidateValue))]
    public string Hello2 { get; set; }

    // must be static
    private void Validate(object value) => _ = Convert.ToInt32(value);
}

public class Validators
{
    // must be public
    internal static void ValidateValue(object value) => _ = Convert.ToInt32(value);
}

Example of how to fix

Fix the attribute argument to match the method name

public class TestClass
{
    [Validator(nameof(Validate))]
    public string Hello1 { get; set; }

    [Validator(typeof(Validators), nameof(Validators.ValidateValue))]
    public string Hello2 { get; set; }

    // must be static
    private static void Validate(object value) => _ = Convert.ToInt32(value);
}

public class Validators
{
    public static void ValidateValue(object value) => _ = Convert.ToInt32(value);
}

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable GQL019
// The code that's violating the rule is on this line.
#pragma warning restore GQL019

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.cs]
dotnet_diagnostic.GQL019.severity = none

For more information, see How to suppress code analysis warnings.

GQL017: Could not find method
GQL018: Parser method must be valid
GQL020: ValidateArguments method must be valid