How to set a struct value T from Type

Question

I'm using the extension from Joel's string-to-nullable-type answer here:

public static Nullable<T> ToNullable<T>(this string s) where T: struct
{
    Nullable<T> result = new Nullable<T>();
    try
    {
        if (!string.IsNullOrEmpty(s) && s.Trim().Length > 0)
        {
            TypeConverter conv = TypeDescriptor.GetConverter(typeof(T));
            result = (T)conv.ConvertFrom(s);
        }
    }
    catch { } 
    return result;
}

And in my code, I've got the data from a Type. Is there a way to cast or use that extension using Type?

UPDATE 1:

var values = from p in xdoc.Descendents("Answers")
         select r.Attribute("Value").Value.ToNullable<Type.GetType(r.DataType)>()

r.DaraType is a data string.

This isn't an answer to your question, but instead of testing (!String.IsNullOrEmpty && s.Trim().Length > 0), you can just test (!String.IsNullOrWhitespace()). — Brent M. Spell, Sep 05 '11 at 23:21
The big question is what do you intend to do with `values` seeing as how you don't know its type at compile time? — Gabe, Sep 06 '11 at 00:27

Ben Robinson · Accepted Answer · 2011-09-06T09:05:34.043

3

No you can't specify a generic type argument to be the result of a method call that returns a Type object.

i.e. this is invalid ToNullable<Type.GetType(r.DataType)>()

The type needs to be evaluated at compile time and if your syntax was valid the compiler could not tell what the type was in result of your linq query.

edited Sep 06 '11 at 09:05

answered Sep 05 '11 at 23:36

Ben Robinson

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How to set a struct value T from Type

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