我是一名新开发人员，并尝试按照本教程在 C# 中开发 Web 服务。我按照该教程中的说明进行了所有操作，但是，我没有从 Northwind 数据库中获取任何数据，当我按下 Invoke 按钮时，我得到了以下页面：
正如您将在本教程中看到的，我没有将 ConnectionString 添加到 web.config 文件中。我应该这样做吗？
我的代码：
public class WSGetCustomerCountryWise : System.Web.Services.WebService
{
public WSGetCustomerCountryWise()
{
//Uncomment the following line if using designed components
//InitializeComponent();
}
[WebMethod(Description = "It will generate Customer List, CountryWise")]
public System.Xml.XmlElement
GetCustomerCountryWise(string sCountry)
{
string sConn = ConfigurationManager.ConnectionStrings["connStr"].ToString();
string sSQL = "select CustomerId, CompanyName, ContactTitle, City from Customers where country = '"+sCountry+"'";
SqlConnection connCustomer = new SqlConnection(sConn);
DataSet dsCustomer = new DataSet();
SqlDataAdapter sda = new SqlDataAdapter(sSQL, sConn);
sda.Fill(dsCustomer);
System.Xml.XmlDataDocument xdd = new System.Xml.XmlDataDocument(dsCustomer);
System.Xml.XmlElement docElem = xdd.DocumentElement;
return docElem;
}
}