C# - validation attributes

Question

I use C# MVC, I have a list:

 public List<int?> SomeList { get; set; }

and when the user try to enter a letter instead of a number, it shows a validation error because the list's type is INT.

I want to add more validation, like "range" (not only) for the list's items (all of them will have the same attributes).

Can I do that? How?

The answer is in your title - with what exactly do you have a problem? — flq, Apr 24 '12 at 12:35
if I put [range(0,4)] before the list, it doesn't work.. I need that it will be for the items in the list, not for the list itself.. — TamarG, Apr 24 '12 at 12:36

SynerCoder · Answer 1 · 2012-04-24T12:51:55.970

0

You might want to look into the source of the rangeattribute, and create your own attribute (http://msdn.microsoft.com/en-us/library/cc668224.aspx) that will validate a generic list with a range.

There ya go.

edited Apr 24 '12 at 12:51

answered Apr 24 '12 at 12:36

SynerCoder

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How does it help me for a list? – TamarG Apr 24 '12 at 12:40
1

I did it! :) I used that - http://stackoverflow.com/questions/9071351/how-to-get-model-validation-to-pickup-attributes-set-on-objects-in-a-list-in-mvc I created a new class that contains only an int field, and it has its own validation attributes, and then created a list of this class. – TamarG Apr 24 '12 at 12:53

score 0 · Answer 2 · answered Apr 24 '12 at 12:46

0

You can always implement the validation yourself, especially if you want to implement arbitrary validation on various criteria

bool validate(int value){
    if ((value < min) || (value > max))
        return false;
}

answered Apr 24 '12 at 12:46

msam

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score 0 · Answer 3 · answered Apr 24 '12 at 12:48

You'll have to create your own class that inherits from List<T>, then you can "hide" the Add method by declaring a new method:

    class TestList : List<int>
{
    public int MinValue { get; set; }
    public int MaxValue { get; set; }

    public TestList(int minValue, int maxValue)
    {
        this.MinValue = minValue;
        this.MaxValue = maxValue;
    }

    public new void Add(int item)
    {
        if (item < MinValue || item > MaxValue)
            throw new ArgumentException("Value is outside the acceptable range");

        base.Add(item);
    }
}

Edit: forgot to throw in the constructor.

C# - validation attributes

3 Answers3