ResourceOwnerPasswordValidator.ValidateAsync C# (CSharp) Method

    public async Task ValidateAsync(ResourceOwnerPasswordValidationContext context)
    {
        var authenticationResult = await _mediator.Send(
            new AuthenticateCommand(context.UserName, context.Password));

        if (authenticationResult.IsAuthenticated)
        {
            context.Result = new GrantValidationResult(
                authenticationResult.User.Id.ToString(),
                "forms", authenticationResult.User.Claims);
        }
        else
        {
            context.Result = new GrantValidationResult(
                TokenRequestErrors.InvalidGrant,
                authenticationResult.AuthenticationError);
        }
    }
}