Question

What will be the best way to implement this method:

Type GetNullableTypeFromType(Type tp);

so that

Type tpString = GetNullableTypeFromType(typeof(string));   // Returns typeof(string)
Type tpInt = GetNullableTypeFromType(typeof(int));   // Returns typeof(int?)

Answer 1

public static Type GetNullableType(Type t)
{
    if (t.IsValueType && (Nullable.GetUnderlyingType(t) == null)) 
        return typeof(Nullable<>).MakeGenericType(t); 
    else
        return t;
}