Net is datetime nullable 3 5
On the offhand chance that your object is already a Date Time, you're performing unnecessary conversions to and from strings. if (o is Date Time) return ( Date Time)o; This also strikes me as something you might be doing for a database item, for example. In which case, I'd encourage you to know and trust your data types and then use existing methods of retrieval. For example, if you have a Data Table with a column Created Date, you should know it's a date, what you might not know is if it has a value if the column is nullable at the database. That's fine, you can handle that in code. var created Date = row. Field< Date Time?>( Created Date There we go, a Date Time?, no coding of a conversion necessary. You can even specify a default and type if to Date Time var created Date = row. Field< Date Time?>( Created Date ). Get Value Or Default( Date Time. Now var created Date = row. Field< Date Time?>( Created Date )? Date Time. Now;.
Abstract This article will help you to understand the Nullable type implementation in C. This article also explains about Coalescing Operator and how CLR has special support for Nullable value type. Introduction As we all know, a value type variable cannot be null. That's why they are called Value Type. Value type has a lot of advantages, however, there are some scenarios where we require value type to hold null also. For instance, If you are retrieving nullable integer column data from database table, and the value in database is null, there is no way you can assign this value to an C int. Let's havea look at another scenario: In Java, java. Util. Date is a reference type, and therefore, the variable of this type can be set to null. However, in CLR, System. Date Time is a value type and a Date Time variable cannot be null. If an application written in Java wants to communicate a date/time to a Web service running on the CLR, there is a problem if the Java application sends null because the CLR has no way to represent this and operate on it. To get rid of these situations, Microsoft added the concept of Nullable types to the CLR. To Understand this, have a look over the definition of System. Nullable
I managed to generate this error twice within a few days while working with the Entity Framework and SQL Server 2012. I had to resort to searching for a resolution on both occasions so I'm posting about it to sear the cause and solution into my brain. First, note the exception type. It is a Sql Exception, so it's being generated by the Sql Client provider. In other words, this is your database talking. The SQL Server datetime datatype is capable of storing dates in the range to, or Jan 1st 1753 to way longer than anyone reading this needs to worry about. The datetime2 data type was introduced in SQL Server 2008. The range of dates that it is capable of storing is to, or Jan 1st 1 AD to way longer than anyone reading this. You get the idea. The. Net datetime is isomorphic with the SQL Server datetime2 type - the range of possible values is the same. The default value for an uninitialised datetime variable is Date Time. Min Value, or. And this is usually the cause of the error message featured in the title of this post. It happens when you do not provide a value for a datetime in your C (or VB) code which is to be stored in a non-nullable datetime field in the database. The. Net variable or property will default to which SQL Server will see as a valid value for a datetime2 field, but then tries to convert to a datetime type to store it in the appropriate field in the database table. As has already been established, is outside of the range of acceptable values for a datetime field. Hence the error message. So what are the possible fixes? Actually, there are a few: 1. Change the storage to Date Time2 in the database. Datetime2 is the recommended type for dates and times in SQL Server 2008 onwards. You will need to explictly map the relevant columns to datetime2 since EF will always map. Net.
Message 0 does not exist or has been deleted. Recent Topics Fog Creek Home.
Public Class Date Helper Private Shared Read Only FIRST_ GOOD_ DATE As New Date Time(1900, 1, 1) Public Shared Function Map Date Less Than1900 To Null( By Val input Date As System. Nullable( Of Date Time) As System. Nullable( Of Date Time) Dim return Date As System. Nullable( Of Date Time) = Nothing If input Date >= FIRST_ GOOD_ DATE Then return Date = input Date End If Return return Date End Function End Class < Test Fixture > _ Public Class As_ A_ Date Helper < Set Up > _ Public Sub I_want_to End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_null_date_when_passed_a_null_nullable_date Dim test Date As System. Nullable( Of Date Time) = Nothing Assert. Are Equal( Nothing, Date Helper. Map Date Less Than1900 To Null(test Date) End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_null_date_when_passed_null Assert. Are Equal( Nothing, Date Helper. Map Date Less Than1900 To Null( Nothing) End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_null_date_when_passed_ Dec_31_1899 Dim test Date As New Date Time(1899, 12, 31) Assert. Are Equal( Nothing, Date Helper. Map Date Less Than1900 To Null(test Date) End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_date_when_passed_ Jan_01_1900 Dim test Date As New Date Time(1900, 1, 1) Assert. Are Equal(test Date, Date Helper. Map Date Less Than1900 To Null(test Date) End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_date_when_passed_normal_date Dim test Date As New Date Time(2008, 8, 6) Assert. Are Equal(test Date, Date Helper. Map Date Less Than1900 To Null(test Date) End Sub < Test > _ Public Sub Verify_ Map Date Less Than1900 To Null_returns_null_date_when_passed_nullable_ Dec_31_1899 Dim test Date As System. Nullable( Of Date Time) = New Date Time(1899, 12, 31) Assert. Are Equal( Nothing, Date Helper. Map Date Less Than1900 To Null(test Date) End Sub < Test > _ Public Sub.
Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Join the Stack Overflow community to: Ask programming questions Answer and help your peers Get recognized for your expertise up vote 39 down vote accepted You need to use. Value first ( Since it's nullable). var short String = your Date. Value. To Short Date String But also check that your Date has a value: if (your Date. Has Value) var short String = your Date. Value. To Short Date String That function is absolutely available within the Date Time class. Please refer to the MSDN documentation for the class: Since Nullable is a generic on top of the Date Time class you will need to use the. Value property of the Date Time? instance to call the underlying class methods as seen below: Date Time? date; String short Date String; short Date String = date. Value. To Short Date String Just be aware that if you attempt this while date is null an exception will be thrown. If you want to be guaranteed to have a value to display, you can use Get Value Or Default in conjunction with the To Short Date String method that other postelike this: your Date. Get Value Or Default. To Short Date String This will show if the value happened to be null. Your Answer draft saved draft discarded lang-cs.