C＃：找不到方法异常（Setter缺失）

Question

I'm facing really strange error while debugging my program. I have a data contract where I added new properties but one of them cause the following exception:

Method not found: 'Void Measurement.set_ContactId(Int32)'.

The data contract looks following:

[DataContract]
public class Measurement
{
    [DataMember]
    public int FactId { get; set; }

    [DataMember]
    public int ContactId { get; set; }
.....

I don't really understand what can be a problem since, as I said, I added some other properties but there was no problem with them.

UPD: The exception is happening on the service side when I try to assign a value to ContactId :

foreach (Measurement m in result.Where(m => m.FactId == factId)){
    m.ContactId = contactId;
  .....

Answer 1

The problem was with some older version of the DLL which was stored in .NET's cache. I made a search on the whole disk for the DLL and deleted all found files (some were in use by the .NET so I had to use Unlocker). After rebuilding the project it worked fine.

Answer 2

If this Measurement class is part of your WCF service, then you have it on both side of your service (client side and server side). Do both side have the same version (where ContactId has a setter)?