Linked Questions
20 questions linked to/from Nullable type as a generic parameter possible?
20
votes
1
answer
3k
views
Why does Nullable<T> not match as a reference type for generic constraints [duplicate]
Possible Duplicate:
Nullable type as a generic parameter possible?
I came across a very weird thing with generic type constraints. I have a class like this:
public SomeClass<T> where T:...
- 64.3k
1
vote
2
answers
288
views
Is it possible to create class that uses nullable int as generic parameter? [duplicate]
I am trying to create class called Stats that uses generic parameter T. I intend to use T as int? or float?. However, when I try to create object of class Stats I get that:
Error 1 The type 'int?' ...
- 327
0
votes
1
answer
305
views
Is it possible to restrict a generic parameter to just accept nullable types? [duplicate]
Possible Duplicate:
Nullable type as a generic parameter possible?
Is creating a C# generic method that accepts (nullable) value type and reference type possible?
In c# I would like to restrict ...
- 566
-1
votes
1
answer
49
views
C#: Strongly type heterogenous container accept nullable [duplicate]
I am trying to adapt the following code, to also acceptable nullable type. Consider this:
public sealed class JsonDictionary
{
private readonly IDictionary<string, object> _data;
public ...
- 12.7k
0
votes
0
answers
24
views
Problem with generic class with a nullable attribute [duplicate]
I have this C# code:
using System;
namespace NullableExample
{
public class PAttribute<T>
{
public T? Value { get; set; }
public bool IsPertinent { get; set; }
...
383
votes
30
answers
528k
views
SQL Data Reader - handling Null column values
I'm using a SQLdatareader to build POCOs from a database. The code works except when it encounters a null value in the database. For example, if the FirstName column in the database contains a null ...
- 28.4k
156
votes
10
answers
80k
views
C# generic type constraint for everything nullable
So I have this class:
public class Foo<T> where T : ???
{
private T item;
public bool IsNull()
{
return item == null;
}
}
Now I am looking for a type constraint that ...
- 1,677
12
votes
2
answers
3k
views
Why T? is not a nullable type?
Why the code below doesn't work?
public T? Method<T>()
{
/*
error CS0403: Cannot convert null to type parameter 'T'
because it could be a non-nullable value type.
Consider ...
- 2,027
1
vote
5
answers
2k
views
Why is my code so slow?
I wrote the following extension method to get an element from a dictionary, or null if the key isn't present:
public static TValue ItemOrNull<TKey, TValue>(this IDictionary<TKey, TValue> ...
- 6,653
4
votes
3
answers
8k
views
How to make Generic parameter T Nullable in C#?
I'm creating a generic method which should be able to return null.
As an example I've created this method GetSecondSmallest(List<T>) below. This function loops through all of the IComparable ...
- 14.2k
1
vote
3
answers
1k
views
Is there a way to define an generic interface with a constraint that the type can be null (but cannot be a value type)?
I'd like to define an generic interface that allows nullable value types (int?, double?, etc.) and class types (which can also be null). I do not want to allow a simple value type. Is there a way to ...
- 3,238
1
vote
1
answer
2k
views
Nullable generic type that can be an int or string
I'm trying to create an interface that will add a column to a database entity which will be used the track the user making changes.
public interface IAuditEntity<TKey>
{
TKey? UpdatedBy { ...
- 4,808
3
votes
5
answers
737
views
Pros and Cons of using "as", "is", "DBNull", ToString() in C#
When reading data from ExecuteReader. It returns me data in IDataReader. When I want to fill this data into my entities I will be assigning Non Nullable values in most of the cases to either Nullable ...
- 34.6k
8
votes
2
answers
2k
views
Tell the caller that a `async Task<T>` method may return null
My situation is similar to the one described Proper nullable annotation for async generic method that may return default(T).
However, I'd like to know the proper way to let the caller know that the &...
- 4,518
0
votes
3
answers
517
views
How to write generic method for casting DBNull value to Nullable?
I have a database with a nullable column foo_date, where Npgsql maps the sql NULL value to an instance of the C# class DBNull. In my C# aggregate I use the type DateTime? for said column. So the ...
- 964