hi experts
1. a sql server 2008 table that contains many columns and some of them are checked "not null"
like this:
create table Book( ID bigint identity ( 1 , 1 ) not null , Name nvarchar 50 null , ISBN nvarchar 10 not null , ......
2. in c#4, visual studio 2010, i use linq to sql. like:
var context = new Model().Books; var query = from b in context select b;
the question is , how can i get only "allowed null" columns? i want linq to sql realize if the field is "allow null" or not? This might help: http://weblogs.asp.net/grantbarrington/archive/2009/03/17/using-reflection-to-determine-whether-an-type-is-nullable-and-get-the-underlying-type.aspx [ ^ ]
There is some information on getting Nullable on msdn ( http://msdn.microsoft.com/en-us/library/ms366789.aspx [ ^ ]), but only for types. You cannot use the object.GetType() to determine if something is Nullable because if you do a GetType() on an int? you just get the result of int. This code will work with typeof() (ie typeof(int?) ):
public static class Extensions public static bool IsNullable( this Type type) return type.IsGenericType && (type.GetGenericTypeDefinition() == typeof (Nullable<>)); This code will work with generics;
public class x < T > public x() var x = typeof(T).IsNullable(); please read this topic from stackoverflow, I think it's what you want to achieve.
http://stackoverflow.com/questions/413084/equivalent-of-sql-isnull-in-linq [ ^ ]
Regards

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