HttpSimpleClientProtocol.BeginInvoke 方法

定义

开始异步调用 XML Web services 的方法。

protected:
 IAsyncResult ^ BeginInvoke(System::String ^ methodName, System::String ^ requestUrl, cli::array <System::Object ^> ^ parameters, AsyncCallback ^ callback, System::Object ^ asyncState);
protected IAsyncResult BeginInvoke (string methodName, string requestUrl, object[] parameters, AsyncCallback callback, object asyncState);
member this.BeginInvoke : string * string * obj[] * AsyncCallback * obj -> IAsyncResult
Protected Function BeginInvoke (methodName As String, requestUrl As String, parameters As Object(), callback As AsyncCallback, asyncState As Object) As IAsyncResult

参数

methodName
String

XML Web services 方法的名称。

requestUrl
String

创建 WebRequest 时要使用的 URL。

parameters
Object[]

一个对象数组,包含要传递到 XML Web services 方法的参数。 数组中值的顺序与派生类的调用方法中的参数顺序对应。

callback
AsyncCallback

异步方法调用完成时要调用的委托。 如果 callbacknull,则不调用委托。

asyncState
Object

客户端提供的其他信息。

返回

一个 IAsyncResult,它可以传递到 EndInvoke(IAsyncResult) 方法以从 XML Web services 方法中获取返回值。

例外

请求到达了服务器计算机,但未被成功处理。

示例

下面的代码示例是一个 ASP.NET Web 窗体,它调用名为 的 MathXML Web 服务。 EnterBtn_Click在 函数中,Web 窗体启动并完成 XML Web 服务方法的Add异步调用。

<%@ Page Language="VB" %>
<html>
    <script language="VB" runat="server">
    Sub EnterBtn_Click(Src As Object, E As EventArgs)
        Dim math As New MyMath.Math()
        
        ' Call to Add XML Web service method asynchronously.
        Dim result As IAsyncResult = math.BeginAdd(Convert.ToInt32(Num1.Text), Convert.ToInt32(Num2.Text), Nothing, Nothing)
        
        ' Wait for the asynchronous call to complete.
        result.AsyncWaitHandle.WaitOne()
        
        ' Complete the asynchronous call to the Add XML Web service method.
        Dim iTotal As Integer = math.EndAdd(result)
        
        Total.Text = "Total: " & iTotal.ToString()
    End Sub 'EnterBtn_Click
 
  </script>
 
    <body>
       <form action="MathClient.aspx" runat=server>
           
          Enter the two numbers you want to add and then press the Total button.
          <p>
          Number 1: <asp:textbox id="Num1" runat=server/>  +
          Number 2: <asp:textbox id="Num2" runat=server/> =
          <asp:button text="Total" Onclick="EnterBtn_Click" runat=server/>
          <p>
          <asp:label id="Total"  runat=server/>
          
       </form>
    </body>
 </html>

下面的代码示例是由以下 XML Math Web 服务的 Web 服务描述语言工具 (Wsdl.exe) 生成的代理类。 BeginAdd在代理类的 方法中BeginInvoke, 方法启动 XML Web 服务方法的Add异步调用。

namespace MyMath
{
   [XmlRootAttribute("snippet1>",Namespace="http://MyMath/",IsNullable=false)]
   public ref class Math: public HttpGetClientProtocol
   {
   public:
      Math()
      {
         this->Url = "http://www.contoso.com/math.asmx";
      }

      [HttpMethodAttribute(System::Web::Services::Protocols::XmlReturnReader::typeid,
      System::Web::Services::Protocols::UrlParameterWriter::typeid)]
      int Add( String^ num1, String^ num2 )
      {
         array<Object^>^temp0 = {num1,num2};
         return  *dynamic_cast<int^>(this->Invoke( "Add", String::Concat( this->Url, "/Add" ), temp0 ));
      }

      IAsyncResult^ BeginAdd( String^ num1, String^ num2, AsyncCallback^ callback, Object^ asyncState )
      {
         array<Object^>^temp1 = {num1,num2};
         return this->BeginInvoke( "Add", String::Concat( this->Url, "/Add" ), temp1, callback, asyncState );
      }

      int EndAdd( IAsyncResult^ asyncResult )
      {
         return  *dynamic_cast<int^>(this->EndInvoke( asyncResult ));
      }
   };
}
namespace MyMath
{
    [XmlRootAttribute("int", Namespace = "http://MyMath/", IsNullable = false)]
    public class Math : HttpGetClientProtocol
    {
        public Math()
        {
            this.Url = "http://www.contoso.com/math.asmx";
        }

        [HttpMethodAttribute(typeof(System.Web.Services.Protocols.XmlReturnReader),
            typeof(System.Web.Services.Protocols.UrlParameterWriter))]
        public int Add(int num1, int num2)
        {
            return ((int)(this.Invoke("Add", ((this.Url) + ("/Add")),
                new object[] { num1, num2 })));
        }

        public IAsyncResult BeginAdd(int num1, int num2, AsyncCallback callback, object asyncState)
        {
            return this.BeginInvoke("Add", ((this.Url) + ("/Add")),
                new object[] { num1, num2 }, callback, asyncState);
        }

        public int EndAdd(IAsyncResult asyncResult)
        {
            return ((int)(this.EndInvoke(asyncResult)));
        }
    }
}
Namespace MyMath
    <XmlRootAttribute("int", Namespace := "http://MyMath/", IsNullable := False)> _
    Public Class Math
        Inherits HttpGetClientProtocol
        
        Public Sub New()
            Me.Url = "http://www.contoso.com/math.asmx"
        End Sub
        
        <HttpMethodAttribute(GetType(XmlReturnReader), GetType(UrlParameterWriter))> _
        Public Function Add(num1 As String, num2 As String) As Integer
            Return CInt(Me.Invoke("Add", Me.Url + "/Add", New Object() {num1, num2}))
        End Function 'Add
        
        
        Public Function BeginAdd(num1 As String, num2 As String, callback As AsyncCallback, asyncState As Object) As IAsyncResult
            Return Me.BeginInvoke("Add", Me.Url + "/Add", New Object() {num1, num2}, callback, asyncState)
        End Function 'BeginAdd
        
        
        Public Function EndAdd(asyncResult As IAsyncResult) As Integer
            Return CInt(Me.EndInvoke(asyncResult))
        End Function 'EndAdd
    End Class
End Namespace 'MyMath

下面的代码示例是 Math XML Web 服务,从中创建了前面的代理类。

<%@ WebService Language="C#" Class="Math"%>
 using System.Web.Services;
 using System;
 
 public class Math {
      [ WebMethod ]
      public int Add(int num1, int num2) {
          return num1+num2;
          }
 }
<%@ WebService Language="VB" Class="Math"%>
Imports System.Web.Services
Imports System

Public Class Math
    <WebMethod()> _
    Public Function Add(num1 As Integer, num2 As Integer) As Integer
        Return num1 + num2
    End Function 'Add
End Class 'Math

注解

参数 methodName 用于查找参数的类型,并返回调用方法的方法的值 BeginInvoke 。 它还用于查找可能已添加到 方法的自定义属性。 SoapDocumentMethodAttributeSoapRpcMethodAttributeXmlElementAttribute 提供有关 HTTP 协议所需的派生方法的其他信息。

asyncState 传入 callback ,并包含在 IAsyncResultBeginInvoke 方法返回的 中。 它将信息从异步调用的上下文传递到 处理中的 callback异步结果时很有用。

适用于

另请参阅