ASP .NET MVC 3 Data Annotations GreaterThan LowerThan for DateTime and int

Question

I would like to know what is the easiest way to have a "Greater Than" & "Lower Than" validation on a ASP.NET MVC 3 form?

I use unobtrusive JavaScript for client validation. I have two DateTime properties (StartDate & EndDate) and I need a validation to be sure that the EndDate is greater than the StartDate. I have another similar case with another form on which I have a MinValue (int) & MaxValue (int).

Does this type of validation exist by default? Or does someone know an article which explains how to implement it?

Answer 1

Could look at the dataannotationsextensions it does Min/Max for int

Also have a look at a foolproof validation it inlcudes GreaterThan comparison for numeric/datetime etc

Answer 2

You can simply do this with custom validation.

[AttributeUsage(AttributeTargets.Property, AllowMultiple=true)]
    public class DateGreaterThanAttribute : ValidationAttribute
    {
        string otherPropertyName;

        public DateGreaterThanAttribute(string otherPropertyName, string errorMessage)
            : base(errorMessage)
        {
            this.otherPropertyName = otherPropertyName;
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            ValidationResult validationResult = ValidationResult.Success;
            try
            {
                // Using reflection we can get a reference to the other date property, in this example the project start date
                var otherPropertyInfo = validationContext.ObjectType.GetProperty(this.otherPropertyName);
                // Let's check that otherProperty is of type DateTime as we expect it to be
                if (otherPropertyInfo.PropertyType.Equals(new DateTime().GetType()))
                {
                    DateTime toValidate = (DateTime)value;
                    DateTime referenceProperty = (DateTime)otherPropertyInfo.GetValue(validationContext.ObjectInstance, null);
                    // if the end date is lower than the start date, than the validationResult will be set to false and return
                    // a properly formatted error message
                    if (toValidate.CompareTo(referenceProperty) < 1)
                    {
                        validationResult = new ValidationResult(ErrorMessageString);
                    }
                }
                else
                {
                    validationResult = new ValidationResult("An error occurred while validating the property. OtherProperty is not of type DateTime");
                }
            }
            catch (Exception ex)
            {
                // Do stuff, i.e. log the exception
                // Let it go through the upper levels, something bad happened
                throw ex;
            }

            return validationResult;
        }
}

and use it in model like

 [DisplayName("Start date")]
    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}", ApplyFormatInEditMode = true)]        
    public DateTime StartDate { get; set; }

    [DisplayName("Estimated end date")]
    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}", ApplyFormatInEditMode = true)]
    [DateGreaterThan("StartDate", "End Date end date must not exceed start date")]
    public DateTime EndDate { get; set; }

This works well with server side validation.For client side validaion you can write the method like GetClientValidationRules like

public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            //string errorMessage = this.FormatErrorMessage(metadata.DisplayName);
            string errorMessage = ErrorMessageString;

            // The value we set here are needed by the jQuery adapter
            ModelClientValidationRule dateGreaterThanRule = new ModelClientValidationRule();
            dateGreaterThanRule.ErrorMessage = errorMessage;
            dateGreaterThanRule.ValidationType = "dategreaterthan"; // This is the name the jQuery adapter will use
            //"otherpropertyname" is the name of the jQuery parameter for the adapter, must be LOWERCASE!
            dateGreaterThanRule.ValidationParameters.Add("otherpropertyname", otherPropertyName);

            yield return dateGreaterThanRule;
        }

Now simply in view

$.validator.addMethod("dategreaterthan", function (value, element, params) {

    return Date.parse(value) > Date.parse($(params).val());
});
$.validator.unobtrusive.adapters.add("dategreaterthan", ["otherpropertyname"], function (options) {
    options.rules["dategreaterthan"] = "#" + options.params.otherpropertyname;
    options.messages["dategreaterthan"] = options.message;
});

You can find more details in this link

Answer 3

I don't know if writing your own validator class is the "easiest" way, but that's what I did.

Usage:

<DataType(DataType.Date)>
Public Property StartDate() As DateTime


<DataType(DataType.Date)>
<DateGreaterThanEqual("StartDate", "end date must be after start date")>
Public Property EndDate() As DateTime

Class:

<AttributeUsage(AttributeTargets.Field Or AttributeTargets.Property, AllowMultiple:=False, Inherited:=False)>
Public Class DateGreaterThanEqualAttribute
    Inherits ValidationAttribute

    Public Sub New(ByVal compareDate As String, ByVal errorMessage As String)
        MyBase.New(errorMessage)
        _compareDate = compareDate
    End Sub
    Public ReadOnly Property CompareDate() As String
        Get
            Return _compareDate
        End Get
    End Property
    Private ReadOnly _compareDate As String

    Protected Overrides Function IsValid(ByVal value As Object, ByVal context As ValidationContext) As ValidationResult
        If value Is Nothing Then
            ' no need to do or check anything
            Return Nothing
        End If
        ' find the other property we need to compare with using reflection
        Dim compareToValue = Nothing
        Dim propAsDate As Date
        Try
            compareToValue = context.ObjectType.GetProperty(CompareDate).GetValue(context.ObjectInstance, Nothing).ToString
            propAsDate = CDate(compareToValue)
        Catch
            Try
                Dim dp As String = CompareDate.Substring(CompareDate.LastIndexOf(".") + 1)
                compareToValue = context.ObjectType.GetProperty(dp).GetValue(context.ObjectInstance, Nothing).ToString
                propAsDate = CDate(compareToValue)
            Catch
                compareToValue = Nothing
            End Try
        End Try

        If compareToValue Is Nothing Then
            'date is not supplied or not valid
            Return Nothing
        End If

        If value < compareToValue Then
            Return New ValidationResult(FormatErrorMessage(context.DisplayName))
        End If

        Return Nothing
    End Function

End Class