Question

我是.Net网络服务编程的新手。我遇到麻烦，从Web服务读取XML响应给我的客户端。

在我的网络服务方面：Service1.asmx.cs代码：

    [WebMethod(Description = "substruction")]
    public double subtract(double i, double j)
    {
        return i - j;
    }


    [WebMethod(Description = "getxml")]
    public XmlDocument GetXML()
    {
        StringBuilder sb = new StringBuilder();
        XmlWriter writer = XmlWriter.Create(sb);

        writer.WriteStartDocument();
        writer.WriteStartElement("People");

        writer.WriteStartElement("Person");
        writer.WriteAttributeString("Name", "Nick");
        writer.WriteEndElement();

        writer.WriteStartElement("Person");
        writer.WriteStartAttribute("Name");
        writer.WriteValue("Kevin");
        writer.WriteEndAttribute();
        writer.WriteEndElement();

        writer.WriteEndElement();
        writer.WriteEndDocument();

        writer.Flush();

        XmlDocument xmlDocument = new XmlDocument();
        xmlDocument.LoadXml(sb.ToString());
        return xmlDocument;

    }

在这里，我创建了两种测试响应的方法。在GetXML中，我创建了一个非常简单的XML并将包XML返回给客户端。

在我的客户方面：

    // Add button click function 
    protected void Button1_Click(object sender, EventArgs e)
    {
        string selectFlag = selectOper.Value;
        localhost.Service1 web = new localhost.Service1(); // Have to be the same name as youre Service1. 
        if (selectFlag.Equals("+"))
        {
            Result.Text = (web.addition(double.Parse(Num1.Text), double.Parse(Num2.Text))).ToString();
        }
        else if (selectFlag.Equals("-"))
        {
            Result.Text = (web.subtract(double.Parse(Num1.Text), double.Parse(Num2.Text))).ToString();
        }

    }

    protected void Button2_Click(object sender, EventArgs e)
    {


        localhost.Service1 web2 = new localhost.Service1(); // Can u please do not be so silly, use different instance name here. 
        Button clickedButton = (Button)sender;

        XmlDocument xmltest = new XmlDocument();
        xmltest = web2.GetXML();

你可以看到我试图让web2.GetXML（）将整个XML放到XmlDoucment中。但是，它说错误1无法隐式转换类型＆＃39;对象＆＃39;到＆＃39; System.Xml.XmlDocument＆＃39;。存在显式转换（您是否缺少演员？）C：\ Documents and Settings \ qili \ My Documents \ Downloads \ WebService3 \ WebService2 \ WebService2 \ Default.aspx.cs 39 24 WebService2

任何提示，我想我做错了什么。但Buttom1_Click方法工作正常。

Answer 1

尝试转换服务响应：

protected void Button2_Click(object sender, EventArgs e)
    {


     localhost.Service1 web2 = new localhost.Service1(); // Can u please do not be so silly, use different instance name here. 
     Button clickedButton = (Button)sender;
     XmlDocument xmltest = new XmlDocument();
     xmltest = (XmlDocument)web2.GetXML();
    }

Answer 2

您应该尝试删除服务引用，重新运行服务，并在客户端添加服务引用。

阅读XML响应webservice

2 个答案: