更新时间:2022-06-27 00:19:53
每个文档:
只有一个InstanceContext对象可用于所有传入呼叫,并且是通话后未回收.如果服务对象没有存在,一个被创建.
Only one InstanceContext object is used for all incoming calls and is not recycled subsequent to the calls. If a service object does not exist, one is created.
因此,只有一个实例,并且在调用后不会清除它.这就像您的WCF服务的Singleton.因此,您需要注意共享内存和资源.
So there is only one instance, and it's not cleaned up after a call is made. This is like a Singleton for your WCF service. So you need to be careful about shared memory and resources.
要回答您的问题-是的,这就是它的工作方式.
To answer your question - yes, this is the way it works.
更新添加了示例:我从MSDN修改了一些示例,以显示 InstanceContextMode.Single
的效果.即使我使用两个不同的客户端,您也会看到操作计数将继续增加.如果我将 InstanceContextMode
更改为 PerCall
,则计数将有所不同(为零).
UPDATE Added sample:
I modified a few samples from MSDN to show the effects of InstanceContextMode.Single
. You'll see the operation count will continue to increment even though I use two different clients. If I change the InstanceContextMode
to PerCall
, the count will be different (it will be zero).
自托管服务:
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
public class CalculatorService : ICalculatorInstance
{
static Object syncObject = new object();
static int instanceCount;
int instanceId;
int operationCount;
public CalculatorService()
{
lock (syncObject)
{
instanceCount++;
instanceId = instanceCount;
}
}
public double Add(double n1, double n2)
{
operationCount++;
return n1 + n2;
}
public double Subtract(double n1, double n2)
{
Interlocked.Increment(ref operationCount);
return n1 - n2;
}
public double Multiply(double n1, double n2)
{
Interlocked.Increment(ref operationCount);
return n1 * n2;
}
public double Divide(double n1, double n2)
{
Interlocked.Increment(ref operationCount);
return n1 / n2;
}
public string GetInstanceContextMode()
{ // Return the InstanceContextMode of the service
ServiceHost host = (ServiceHost)OperationContext.Current.Host;
ServiceBehaviorAttribute behavior = host.Description.Behaviors.Find<ServiceBehaviorAttribute>();
return behavior.InstanceContextMode.ToString();
}
public int GetInstanceId()
{ // Return the id for this instance
return instanceId;
}
public int GetOperationCount()
{ // Return the number of ICalculator operations performed
// on this instance
lock (syncObject)
{
return operationCount;
}
}
}
public class Program
{
static void Main(string[] args)
{
Uri baseAddress = new Uri("http://localhost:12345/calc");
using (ServiceHost host = new ServiceHost(typeof(CalculatorService), baseAddress))
{
// Enable metadata publishing.
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
host.Description.Behaviors.Add(smb);
// Open the ServiceHost to start listening for messages. Since
// no endpoints are explicitly configured, the runtime will create
// one endpoint per base address for each service contract implemented
// by the service.
host.Open();
Console.WriteLine("The service is ready at {0}", baseAddress);
Console.WriteLine("Press <Enter> to stop the service.");
Console.ReadLine();
// Close the ServiceHost.
host.Close();
}
Console.WriteLine();
Console.WriteLine("Press <ENTER> to terminate client.");
Console.ReadLine();
}
}
客户端:
class Program
{
static void Main()
{
// Create a client.
CalculatorInstanceClient client = new CalculatorInstanceClient();
string instanceMode = client.GetInstanceContextMode();
Console.WriteLine("InstanceContextMode: {0}", instanceMode);
Console.WriteLine("client1's turn");
Console.WriteLine("2 + 2 = {0}", client.Add(2, 2).ToString());
Console.WriteLine("3 - 1 = {0}", client.Subtract(3, 1).ToString());
Console.WriteLine("number of operations = {0}", client.GetOperationCount().ToString());
// Create a second client.
CalculatorInstanceClient client2 = new CalculatorInstanceClient();
Console.WriteLine("client2's turn");
Console.WriteLine("2 + 2 = {0}", client2.Add(2, 2).ToString());
Console.WriteLine("3 - 1 = {0}", client2.Subtract(3, 1).ToString());
Console.WriteLine("number of operations = {0}", client2.GetOperationCount().ToString());
Console.WriteLine();
Console.WriteLine("Press <ENTER> to terminate client.");
Console.ReadLine();
}
}