Failed to get wcf data member value

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C#

WCF

DataContract

I am trying to add a data member to wcf application but failed to get its value. I created a DataContract class in my service and set the value to an object of this DataContract class in my console application. However, I failed to get the value I assigned. Here are the service codes.

namespace WcfServices
{
    [ServiceContract]
    public interface ICDNManagementService
    {
        [OperationContract]
        [WebInvoke(Method = "POST", UriTemplate = "SetBlobInformation")]
        void SetBlobInformation(BlobInformation blobInformation);
        [OperationContract]
        [WebInvoke(Method = "GET", UriTemplate = "GetBlobInformation")]
        BlobInformation GetBlobInformation();

    }

    [DataContract]
    public class BlobInformation
    {
        string _azureBlobUrl;

        [DataMember]
        public string azureBlobUrl
        {
            get
            {
                return _azureBlobUrl;
            }
            set
            {
                _azureBlobUrl = value;
            }
        }
    }
}

And

namespace WcfServices
{
    public class CDNManagementService : ICDNManagementService
    {
        BlobInformation _blobInformation = new BlobInformation();

        public CDNManagementService()
        {
            _blobInformation.azureBlobUrl = "DefaultUrl";
        }

        public void SetBlobInformation(BlobInformation blobInformation)
        {
            Logger.Log("azureBlobUrl= " + blobInformation.azureBlobUrl);
            Logger.Log("Before SetBlobInformation: " + _blobInformation.azureBlobUrl);
            _blobInformation = blobInformation;
            Logger.Log("After SetBlobInformation: " + _blobInformation.azureBlobUrl);

        }

        public BlobInformation GetBlobInformation()
        {
            Logger.Log("In GetBlobInformation: " + _blobInformation.azureBlobUrl);
            return _blobInformation;            
        }
    }
}

Client code

namespace StringParser
{
    class Program
    {
        static void Main(string[] args)
        {
            string blobUrl = "MyBlobUrl";

            CDNManagementService objCDNManagementService = new CDNManagementService();
            BlobInformation objBlobInformation = new BlobInformation();

            objBlobInformation = objCDNManagementService.GetBlobInformation();
            Console.WriteLine(objBlobInformation.azureBlobUrl);

            objBlobInformation.azureBlobUrl = blobUrl;
            objCDNManagementService.SetBlobInformation(objBlobInformation);


            BlobInformation tmpBlobInformation = new BlobInformation();

            tmpBlobInformation = objCDNManagementService.GetBlobInformation();
            Console.WriteLine(tmpBlobInformation.azureBlobUrl);

            Console.WriteLine("Hello World");

        }
    }
}

Console outputs

DefaultUrl
DefaultUrl
Hello World

Messages logged

In GetBlobInformation: DefaultUrl
azureBlobUrl= MyBlobUrl
Before SetBlobInformation: DefaultUrl
After SetBlobInformation: MyBlobUrl
In GetBlobInformation: DefaultUrl

I didn't get "MyBlobUrl" when I invoke GetBlobInformation the second time. It seems that the constructor was invoked before invoking GetBlobInformation the second time. Does anybody know what is going on here? Thanks.

What I have tried:

I added a constructor to the service to check the values.