Validation attribute not comparing values properly RRS feed

  • Question

  • User212939177 posted


    I have a custom validation attribute which aims to compare the values of two other properties in a class in order to assess the validity of a another property. As an example, I have a text box for the name of a department, but a user can also click a checkbox to say it's the same department as the one they work in and can also select a department from a list. The text box is intended for when the user wishes to add a new department for the purposes of what they're entering. 

    For this to work I need validation which indicates that the DepartmentName(the text box) field is Required when SameDepartment(the checkbox) and DepartmentID(the combo) are both null. Here is the code for the validation attribute I've developed: 

        public class ValidationAttributes
            public class RequiredIfTwo : RequiredAttribute
                private String Property1Name { get; set; }
                private Object Desired1Value { get; set; }
                private String Property2Name { get; set; }
                private Object Desired2Value { get; set; }
                public RequiredIfTwo(String property1Name, Object desired1value, String property2Name, Object desired2value)
                    Property1Name = property1Name;
                    Desired1Value = desired1value;
                    Property2Name = property2Name;
                    Desired2Value = desired2value;
                protected override ValidationResult IsValid(object value, ValidationContext context)
                    Object instance = context.ObjectInstance;
                    Type type = instance.GetType();
                    Object property1value = type.GetProperty(Property1Name).GetValue(instance, null);
                    Object property2value = type.GetProperty(Property2Name).GetValue(instance, null);
                    if (property1value == Desired1Value && property2value == Desired2Value)
                        ValidationResult result = base.IsValid(value, context);
                        return result;
                    return ValidationResult.Success;

    Here's how it's used in the viewmodel:

            [RequiredIfTwo("PlacementDepartmentName", null, "SameDepartment", false,
            ErrorMessage = "A host department needs to be selected or added")]
            public int? PlacementDepartmentId { get; set; }
            [RequiredIfTwo("PlacementDepartmentId", null, "SameDepartment", false,
            ErrorMessage = "Host department's name needs to be added when creating a department")]
            public string PlacementDepartmentName { get; set; }

    public bool SameDepartment { get; set; }

    When I run the page and don't enter anything in any of the three fields the validation is still returning a success. I've run it in debug and can see that the values meet the requirements, here is the output from the immediate window when I query various parts of the If statement:

    ? property1value == Desired1Value && property2value == Desired2Value

    -- overall statement not returning true

    ? property1value == Desired1Value

    -- first part is working ok 

    ? property2value == Desired2Value

    -- second part not

    ? property2value
    ? Desired2Value

    -- But both values are showing as false so why is the comparison not returning true? 

    Thursday, November 15, 2018 3:58 PM

All replies

  • User1520731567 posted

    Hi lcift61,

    if (property1value == Desired1Value && property2value == Desired2Value)

    You should pay attention to their data type.

    If comparing two Object ,

    Only the pointer to the object points to the same address is true.

    And as I can see in your code,

    property2value maybe  a string type,and Desired2Value maybe a bool type.

    You could add breakpoints to check their types.

    Best Regards.

    Yuki Tao

    Friday, November 16, 2018 10:09 AM