nullable

Is there a converter in .NET 4.0 that supports conversions between nullable types to shorten instructions like: bool? nullableBool = GetSomething(); byte? nbyte = nullableBool.HasValue ? (byte?)Convert.ToByte(nullableBool.Value) : null; Not that I am aware of. You could just write a helper method like this: public Nullable<TTarget> NullableConvert<TSource, TTarget>( Nullable<TSource> source, Func<TSource, TTarget> converter) where TTarget: struct where TSource: struct { return source.HasValue ? (Nullable<TTarget>)converter(source.Value) : null; } Call it like this: byte? nbyte =

Could some one help, how would I instruct automap to have not-null for a column? public class Paper : Entity { public Paper() { } [DomainSignature] [NotNull, NotEmpty] public virtual string ReferenceNumber { get; set; } [NotNull] public virtual Int32 SessionWeek { get; set; } } But I am getting the following: <column name="SessionWeek"/> I know it can be done using fluent-map. but i would like to know it in auto-mapping way. Thank you. Also, for reference properties ReferenceConvention need to be done. This is the code that works: public class ColumnNullConvention : IPropertyConvention {

how to create setter and getter Properties for nullable datetime. for example: private DateTime mTimeStamp; public DateTime TimeStamp { get { return mTimeStamp; } set { mTimeStamp = value; } } Does nullable attributes support setter and getter or have i to declare it public? private DateTime? mTimeStamp; public DateTime TimeStamp { } You can just do this instead: public DateTime? TimeStamp { get; set; } If you were having trouble with the compiler it's probably because you only changed one of the associated parts - either the private member variable or the property's data type. They need to

I know one of the breaking changes with NHibernate 2.* is that the NHibernate.Nullables are no longer supported. Therefore, what do you use in your mapping file to map the nullable DateTime? type? For i.e.: Understandably doesn't work: <property name="CreateDate" column="CreateDate" type="DateTime?" not-null="false" /> And no longer supported: <property name="ModifiedDate" column="ModifiedDate" type="Nullables.NHibernate.NullableDateTimeType, Nullables.NHibernate" not-null="false"/> I know it must be so obvious, but I'm not finding it! Answer is as simple as: NHibernate will reflect over the

I have a number of methods doing next: var result = command.ExecuteScalar() as Int32?; if(result.HasValue) { return result.Value; } else { throw new Exception(); // just an example, in my code I throw my own exception } I wish I could use operator ?? like this: return command.ExecuteScalar() as Int32? ?? throw new Exception(); but it generates a compilation error. Is it possible to rewrite my code or there is only one way to do that? For C# 7 In C# 7, throw becomes an expression, so it's fine to use exactly the code described in the question. For C# 6 and earlier You can't do that directly in

dim val1 As Integer? = If(5 > 2, Nothing, 43) ' val1 = 0 dim val1 As Integer? = If(5 > 2, Nothing, Nothing) ' val1 = Nothing What gives? Is this a bug, or am I overlooking something? The problem is that Nothing in VB.NET works differently than, for example, null in C#. When Nothing is used in the context of a value type (such as Integer ) it represents the default value of that type. In this case, that's 0. In your first example, both branches of the ternary operator are valid Integer values. The true branch represents 0 and the false branch represents 43. In the second example, neither branch