Mar 04, 2015 reading time 6 minutes

ASP.NET Helpers by Offering Solutions

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I released a new version of the ASP.NET Helpers by Offering Solutions:

Nuget: AspNetHelpers by Offering Solutions

which includes

ViewModelBase
SubmitModelBase
ModelValidator (for easier validation)

and features like

Nullcheck with Exception
Nullcheck with returning the type if not null, otherwise exception
Return bool value if something is null
Checking enumerable if its null or empty
Checks if a string is a timespan
Checks if a string is an email
Converts a string to datetime
Converts a string to timespan
Checks a string for null, empty or a given length (e.g. for password purposes)
Checks if a HttpPostedFile has a specific format
Checks if a HttpPostedFile is an image
Checks if a string can be converted to double
Converts a string to double

Why ViewModels and Submitmodels you can read this here and here

ViewModelBase and SubmitModelBase are two baseclasses for the introduced view- and submitmodels.

public class AccountRegisterViewModel : ViewModelBase
{
    public AccountRegisterSubmitModel SubmitModel { get; set; }

    public AccountRegisterViewModel()
    {
        Url = "~/Here/Goes/My/Url.cshtml";
    }
}

And you can access InfoMessages, SuccessMessages and ErrorMessages now from your ViewModel.

In your view you are filling up your submitmodel and sending it again to your Server. There you can now validate it:

public AccountRegisterViewModel RegisterUser(AccountRegisterSubmitModel submitModel)
{
    AccountRegisterViewModel viewModel = GetAccountRegisterViewMmodel(submitModel);

    try
    {
        if (!_modelValidator.IsSubmitModelValid(viewModel, submitModel))
        {
            return viewModel;
        }

        // Do some stuff
    }
    catch (Exception)
    {
        viewModel.ErrorMessages.Add("There was an error. Can not register.");
    }

    return viewModel;
}

In this exampe the ModelValidator in the NuGet above is used which you register with Ninject for example like this:

kernel.Bind(typeof(IModelValidator)).To(typeof(ModelValidatorImpl));

If you validate with the validator, your Errormessages are getting automatically filled with those defined in your submitmodel and you can easily return it. Of course you can do it the long way like this:

public AccountRegisterViewModel RegisterUser(AccountRegisterSubmitModel submitModel)
{
    AccountRegisterViewModel viewModel = GetAccountRegisterViewMmodel(submitModel);

    try
    {
        ReadOnlyCollection<string> errors;
        if (!submitModel.IsValid(out errors))
        {
            viewModel.ErrorMessages.AddRange(errors);
            return viewModel;
        }

        // Do some stuff
    }
    catch (Exception)
    {
        viewModel.ErrorMessages.Add("There was an error. Can not register.");
    }

    return viewModel;
}

static void Main(string[] args)
{
    //Throws an exception
    Person person = null;
    person.CheckIsNull();

    // Throws an exception if null, gives you back the type otherwise --> Good for DI in public methods
    Person myPerson = person.CheckIsNull("Person must not be null");

    // Is true in this case
    bool personIsNull = person.IsNull();

    person = new Person() {Id = 1, Name = "Fabian"};
    List<Person> listOfPersons = new List<Person>() {person};

    //should be false
    bool isNullOrEmpty = listOfPersons.IsNullOrEmpty();

    // Checks a string for a valid TimeSpan
    string timeSpanToCheck = "11:20";
    bool isTimeSpan = timeSpanToCheck.IsTimeSpan();

    // Checks if a string is a valid email or not
    string email = "dont@ask.me";
    bool isEmail = email.IsEmail();

    //Converts a string to datetime
    string toDateTime = "01.01.2010";
    DateTime dateTime = toDateTime.ToDateTime();

    // COnverts a string to Timespan
    timeSpanToCheck = "11:20";
    TimeSpan timeSpan = timeSpanToCheck.ToTimeSpan();

    //Cheks, if a password has a specific length or is null or empty
    string password = "TheseAreAtLeastEightSigns";
    bool isValidPassword = password.IsValidPassword(8);

    // Checks if a file has a given format...
    HttpPostedFileBase httpPostedFile = null;//...
    bool hasFormat = httpPostedFile.HasFormat("txt");

    // ... or wth multiple extensions
    hasFormat = httpPostedFile.HasFormat("txt", "pdf");

    // Checks if a file is an image...
    bool isImage = httpPostedFile.IsImage();

    // ...also with formats
    isImage = httpPostedFile.IsImage("jpg", "gif");

    //Checks if a value is a double value (separation with . or ,
    string doubleToCheck = "3.5";
    bool isDouble = doubleToCheck.IsDouble();

    //COnverts a string to double
    doubleToCheck = "3.5";
    double doubleValue = doubleToCheck.ToDouble();
}

So, this is it. Hope you enjoy!

Regards

Fabian