HOW TO：在使用 ASP.NET 建立的 Web 服務中管理狀態

本主題專門說明舊有技術。 應該使用下列建立 XML Web Service 及 XML Web Service 用戶端： Windows Communication Foundation.

當實作 Web 服務的類別衍生自 WebService 類別時，Web 服務就像其他 ASP.NET 應用程式一樣，可以存取相同的狀態管理選項。WebService 類別包含許多通用 ASP.NET 物件，包括 Session 和 Application 物件。

存取及儲存特定用戶端工作階段的特定狀態

1. 宣告 Web 服務。

   <%@ WebService Language="C#" Class="ServerUsage" %>
   

   <%@ WebService Language="VB" Class="ServerUsage" %>
   

2. 加入 System.Web.Services 命名空間的參考。

   using System.Web.Services;
   

   Imports System.Web.Services
   

3. 從 WebService 衍生實作 Web 服務的類別。

   public class ServerUsage : WebService 
   

   Public Class ServerUsage : Inherits WebService
   

4. 宣告 Web 服務方法，並將 WebMethod 屬性 (Attribute) 的 EnableSession 屬性 (Property) 設定為 true。

   [ WebMethod(EnableSession=true) ]
   public int PerSessionServiceUsage()
   

   < WebMethod(EnableSession:=True) > _
   Public Function PerSessionServiceUsage() As Integer
   

5. 在 Session 中儲存狀態，這會指定狀態名稱以供稍後擷取。在下列範例中，值 1 是儲存在一個名為 MyServiceUsage 的狀態變數。

   Session["MyServiceUsage"] = 1;
   

   Session("MyServiceUsage") = 1
   

6. 存取 Session 中儲存的狀態變數。

   在下列範例中，會存取 MyServiceUsage 狀態變數以遞增其值。

   Session["MyServiceUsage"] = ((int) Session["MyServiceUsage"]) + 1;
   

   Session("MyServiceUsage") = CInt(Session("MyServiceUsage")) + 1
   

存取及儲存裝載 Web 服務的 Web 應用程式特定的狀態

1. 宣告 Web 服務。

   <%@ WebService Language="C#" Class="ServerUsage" %>
   

   <%@ WebService Language="VB" Class="ServerUsage" %>
   

2. 加入 System.Web.Services 命名空間的參考。

   using System.Web.Services;
   

   Imports System.Web.Services
   

3. 從 WebService 衍生實作 Web 服務的類別。

   public class ServerUsage : WebService
   

   Public Class ServerUsage : Inherits WebService
   

4. 宣告 Web 服務方法。

   [ WebMethod ]
   public int PerSessionServiceUsage()
   

   < WebMethod > _
   Public Function PerSessionServiceUsage() As Integer
   

5. 在 Application 中儲存狀態，這會指定狀態名稱以供稍後擷取。在下列範例中，值 1 儲存在一個名為 appMyServiceUsage 的狀態變數中。

   Application["appMyServiceUsage"] = 1;
   

   Application("appMyServiceUsage") = 1
   

6. 存取 Application 中儲存的狀態變數。

   在下列範例中，會存取 appMyServiceUsage 狀態變數以遞增其值。

   Application["appMyServiceUsage"] =
      ((int) Application["appMyServiceUsage"]) + 1;
   

   Application("appMyServiceUsage") = _
      CInt(Application("appMyServiceUsage")) + 1
   

範例

<%@ WebService Language="C#" Class="ServerUsage" %>
using System.Web.Services;

public class ServerUsage : WebService {
   [ WebMethod(Description="Number of times this service has been accessed.") ]
   public int ServiceUsage() {
     // If the Web service method hasn't been accessed,
     // initialize it to 1.
     if (Application["appMyServiceUsage"] == null) 
     {
       Application["appMyServiceUsage"] = 1;
     }
     else
     {
     // Increment the usage count.
       Application["appMyServiceUsage"] = ((int) Application["appMyServiceUsage"]) + 1;
     }
     return  (int) Application["appMyServiceUsage"];
   }

   [ WebMethod(Description="Number of times a particular client session has accessed this Web service method.",EnableSession=true) ]
   public int PerSessionServiceUsage() {
     // If the Web service method hasn't been accessed, initialize
     // it to 1.
     if (Session["MyServiceUsage"] == null) 
     {
       Session["MyServiceUsage"] = 1;
     }
     else
     {
     // Increment the usage count.
       Session["MyServiceUsage"] = ((int) Session["MyServiceUsage"]) + 1;
     }
     return  (int) Session["MyServiceUsage"];
   }
}

<%@ WebService Language="VB" Class="ServerUsage" %>
Imports System.Web.Services

Public Class ServerUsage
    Inherits WebService
    
<WebMethod(Description := "Number of times this service has been accessed.")> _
    Public Function ServiceUsage() As Integer
        ' If the Web service method hasn't been accessed, initialize
        ' it to 1.
        If Application("appMyServiceUsage") Is Nothing Then
            Application("appMyServiceUsage") = 1
        Else
            ' Increment the usage count.
            Application("appMyServiceUsage") = _
               CInt(Application("appMyServiceUsage")) + 1
        End If
        Return CInt(Application("appMyServiceUsage"))
    End Function    
    
<WebMethod(Description := "Number of times a particular client session has accessed this Web service method.", EnableSession := True)> _
    Public Function  PerSessionServiceUsage() As Integer
       ' If the Web service method hasn't been accessed,
       ' initialize it to 1.
        If Session("MyServiceUsage") Is Nothing Then
            Session("MyServiceUsage") = 1
        Else
            ' Increment the usage count.
           Session("MyServiceUsage") = CInt(Session("MyServiceUsage")) + 1
        End If
        Return CInt(Session("MyServiceUsage"))
    End Function
    
End Class

另請參閱

其他資源

ASP.NET State Management