C# WCF 无法更改类属性

我正在用传感器做一些物联网的事情，我正在尝试改变温度值。我遇到的麻烦是我不能改变我在课堂上的财产。我正在使用接口、类传感器和实现接口的类。看看下面的代码。波纹管是类方法 ChangeTemp（），仅用于测试

public string ChangeTemp()
{
    TemperaturaZrak = 12; //property value change - class sensor
    return TemperaturaZrak.ToString();//just for test if really change value
}

接口协定定义

[OperationContract]
string changeProperty();

实现接口的类

public string changeProperty()
{
    return sr.ChangeTemp(); //web service return new temperature?
}

全类传感器

[DataContract(Name ="SmartRoomClass")]
public  class SmartRoomClass
{
    private double t1;
    private double t2;
    [DataMember(Name = "temperaturaZrak")]
    public double TemperaturaZrak //getter,setter
    {
        get;
        set;
    }
    public SmartRoomClass() //constructor
    {
        TemperaturaZrak = 15;
    }
    public  void CheckTemperature1(double t1, double t2)
    {
        if (TemperaturaZrak >= t1)
        {
            TemperaturaZrak = 26;
        }
        if (TemperaturaZrak <= t2)
        {
            TemperaturaZrak = 22;
        }
    }
}

服务

namespace vaja_2sua.Services
{
    public class SmartRoom : ISmartRoom
    {
        SmartRoomClass sr = new SmartRoomClass();
        public void checkTemperature(double t1, double t2)
        {
            sr.CheckTemperature1(t1, t2);
        }
        public bool checkTemperature(double temperatura)
        {
            if (temperatura > 40)
                return true;
            else
                return false;
        }
        public  double getAirTemperature()
        {
            return sr.TemperaturaZrak;
        }
    }
}

接口

[ServiceContract(Name= "ISmartRoom")]
public interface ISmartRoom
{
    [OperationContract]
    void checkTemperature(double t1, double t2);
    [OperationContract(Name = "GetAirTemperature")]
    double getAirTemperature();
}

如果需要，我可以提供更多信息。问候。