WCF distributed development Common error Resolution (4)

WCF distributed development Common error Resolution (4): The type or namespace name ' DataContract ' could is not found DataContract cannot find

We are developing a WCF project, and we have this error when we define the data contract:

DataContract, DataMember, DataMemberAttribute cannot be found, as shown in figure:

The type or namespace name ' DataContract ' could is found (are you missing a using directive or a assembly?) E:\CodesVs2008\WCFServiceIISHostFrankXuLei\WcfServiceLib\WcfServiceLib\IService1.cs 6 Wcfservicelib

The type or namespace name ' DataMember ' could is found (are you missing a using directive or a assembly?) E : \codesvs2008\wcfserviceiishostfrankxulei\wcfservicelib\wcfservicelib\iservice1.cs WcfServiceLib

The type or namespace name ' DataMemberAttribute ' could is found (are you missing a using directive or a assembly Rence?) E:\CodesVs2008\WCFServiceIISHostFrankXuLei\WcfServiceLib\WcfServiceLib\IService1.cs Wcfservicelib

Workaround, add a reference to the System.Runtime.Serialization assembly in your project.

Life Reference assembly:

Using System.Runtime.Serialization;

Compilation succeeds.