Is class or struct

Question

How do I check is the type class or struct?

 protected   T GetNullValue<T>(IDataReader reader, int ordinalId)
    {
        if (reader.IsDBNull(ordinalId))
        {
            //if T is struct.....
            //else if I is class
        }
        return (T)reader.GetValue(ordinalId);
    }

You may find this answer helpful: http://stackoverflow.com/questions/2713900/how-to-determine-if-a-net-type-is-a-custom-struct — Aim Kai, Mar 07 '11 at 17:54
@Aim - I'm not so sure of that. The accepted answer is particularly bad in my opinion. — ChaosPandion, Mar 07 '11 at 17:55
it is bad form to tack on another question on your existing question like that. It makes the existing answers invalid and the whole post confusing for people later on. — C. Ross, Mar 07 '11 at 19:15

score 7 · Accepted Answer · answered Mar 07 '11 at 17:54

7

if (default(T) is ValueType)
   ...

is the most efficient thing I can come up with at the moment.

answered Mar 07 '11 at 17:54

user541686

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C. Ross · Answer 2 · 2011-03-07T20:29:48.940

3

Get the Type class for the object, and check it.

Type t = reader.GetValue(ordinalId).GetType();
if (t.IsValueType){
    //Struct
} else { 
    //Class
}

I suspect you will be using the Type object later on in your code, if you're trying to dynamically handle the results.

edited Mar 07 '11 at 20:29

answered Mar 07 '11 at 17:58

C. Ross

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That code won't compile. You can't use `typeof` with an object instance, you have to use `GetType()` – thecoop Mar 07 '11 at 20:21

score 2 · Answer 3 · answered Mar 07 '11 at 18:38

2

If T is a value type, it cannot be null. To make a value type nullable, you have to use the System.Nullable struct.

answered Mar 07 '11 at 18:38

tugudum

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Is class or struct

3 Answers3