nullable

So, a couple of questions, actually: An int ( Int32 ) is specified to be (obviously) 32 bits. What about an int? ( Nullable<int> )? My gut tells me that it would be 32 bits for the integer plus 8 more bits for the boolean, but perhaps the implementation is more intricate than that. I would have answered my own question using sizeof(int?) ; but as int? is a managed type this is not allowed. I understand that the size of a type may be platform-dependent, and that in the case of objects which contain references to other objects, a sizeof -like operation would be misleading. However, is there a

I'm new in C#. In c# I can't set value of a structure to null how can I create a structure with null value support? MrWednesday Structs and value types can be made nullable by using the Generic Nullable<> class to wrap it. For instance: Nullable<int> num1 = null; C# provides a language feature for this by adding a question mark after the type: int? num1 = null; Same should work for any value type including structs. MSDN Explanation: Nullable Types (c#) You can use Nullable<T> which has an alias in C#. Keep in mind that the struct itself is not really null (The compiler treats the null

a bool variable could hold true or false, while bool? could be null as well. Why would we need a third value for bool ? If it is not true , what ever it is, it is == false Can you suggest a scenario where I would fancy a bool? instead. Thanks Something can be true, false or undefined for many reasons. How would one answer "Is your third child a girl?" if one only has two children? Both true and false are incorrect. Null would be appropriate as saying that the comparison doesn't apply. Various answers discuss the importance of nullable types in general. There is an additional answer for the

I have a question on how to determine an object's Nullable property type. ObjectA has a property DateTime? CreateDate; When I iterate through its properties like the following code, how do I check if a property is a Nullable DateTime type? foreach (PropertyInfo pi in ObjectA.GetType().GetProperties()) { //do the compare here } pi.PropertyType == typeof(DateTime?) pi.PropertyType == typeof(Nullable<DateTime>); Try: property.PropertyType.Equals(typeof(DateTime?)) 来源： https://stackoverflow.com/questions/1180730/c-sharp-determine-a-nullable-property-datetime-type-when-using-reflection

I have a problem inserting NULL in Django. I mean i don't know how to do this. I have function, lets call it find_position , then i have field in model like position (IntegerField, null=True, blank=True). This function inspect some html code, and if it match with some regex, it returns integer, but if it doesn't find - have to return NULL or None or something that I can put in database. def find_position(self, to_find, something): ... if re.search(to_find, something): return i + (page * 10) + 1 return NULL # or what i have to return here? And i have this: _position = find_position(to_find,