WS Interoperability Tip of the Week. Null dates.

re: WS Interoperability Tip of the Week. Null dates.

Sean — Sat, 08 May 2004 04:57:00 GMT

public class Foo
{
public Nullable<DateTime> Time { get; set; }
}

;)

re: WS Interoperability Tip of the Week. Null dates.

Sean — Sat, 08 May 2004 05:02:00 GMT

*bangs head on desk* Web Service!

public class Foo : WebService
{
[WebMethod]
[return:XmlElement("Time", DataType="time")]
public Nullable<DateTime> Time { get; set; }
}

will it work?

re: WS Interoperability Tip of the Week. Null dates.

Beat Schwegler — Sat, 08 May 2004 14:24:00 GMT

Sean, according to Don's post will ASMX for whidbey support Nullable<T>
For more info: http://www.gotdotnet.com/team/dbox/default.aspx?key=2004-04-21T07:51:45Z

re: WS Interoperability Tip of the Week. Null dates.

Sean — Sun, 09 May 2004 05:51:00 GMT

Good info, thanks.

WS Interoperability Tip of the Week. Null dates

Christopher Steen - Learning .NET — Mon, 10 May 2004 20:41:00 GMT

[ Via C# Items ]WS Interoperability Tip of the Week. Null dates. One Web services interoperability issue that I have been investigating recently has to do with using null DateTime values between .NET and Java.  Here's the problem:System.DateTime in the CLR is considered a value...

re: WS Interoperability Tip of the Week. Null dates.

Dino Chiesa — Wed, 28 Jul 2004 01:09:00 GMT

I think this is an issue that the developer needs to be aware of, but if s/he follows good practices, there will be no terrible problems.

Starting from a WSDL that specifies a field in a complexType as xsd:date, the .NET client-side proxy or server-side skeleton that is generated employs the (little-known?) feature in XML Serialization that:
when you have a value-type property of name Xxxx
and an additional field of name XxxxSpecified, which is a bool, and is decorated with [XmlIgnore]

...then, the value of the bool indicates whether the value type is "null" or not.

In other words, in case #1, you just set XxxSpecified to false, and you will send a "nil" xsd:date to your Java counterpart.

In case #2, just check XxxSpecified for false before evaluating the value of the property. This works with any value type, including DateTime.

See http://msdn.microsoft.com/library/en-us/cpref/html/frlrfSystemXmlSerializationXmlSerializerClassTopic.asp
for the doc on this (look for the discussion on propertyNameSpecified).

re: WS Interoperability Tip of the Week. Null dates.

Dino Chiesa — Fri, 30 Jul 2004 15:24:00 GMT

Ahh, I think I have misunderstood the issue.
If the interface specifies minOccurs=1, then a null date will actually appear in the XML message as something like <Date xsi:nil='1'/>. This is the thing that causes .NET to choke with a FormatException.

You can mitigate the problem without changing the server interface or implementation - in other words just by doing some special handling on the client side.

De-serialize as a string and set a hidden DateTime field behind it. Eg, rather than
public class MyType {
public System.DateTime DateTimeField;
}

you can do:

public class MyType{

private static string formatString= "yyyy-MM-ddTHH:mm:ss.fffffffzzz";
private static System.Globalization.CultureInfo CInfo= new System.Globalization.CultureInfo("en-US", true);

[XmlIgnore] public System.DateTime internal_DateTimeField;
[XmlIgnore] public bool DateTimeFieldIsNull;

[XmlElement(IsNullable=true)]
public string DateTimeField {
set {
if ((value!=null) && (value != "")) {
internal_DateTimeField= System.DateTime.ParseExact(value, formatString, CInfo);
DateTimeFieldIsNull= false;
}
else
DateTimeFieldIsNull= true;
}
get {
return (DateTimeFieldIsNull) ?
null :
internal_DateTimeField.ToString(formatString) ;
}
}
}

Best-Practices-First Development, please!

António Cruz — Sun, 23 Jul 2006 04:20:37 GMT

Actualmente, existem várias abordagens que podemos usar para desenvolver serviços.
Destacam-se duas:...

Best Practices-First Development

O Blog do Cruz — Sun, 23 Jul 2006 05:26:16 GMT

Best Practices-First Development

António Cruz — Sat, 29 Jul 2006 23:06:20 GMT

Actualmente existem várias abordagens que podemos usar para desenvolver serviços. Destacam-se duas: ...