C#怎么连接Webservice服务？

Question

如题，我要做一个基于sql数据库访问的C#应用程序，请教别人之后我知道需要把数据库服务部署到网站上，别人才可以远程访问我的数据库。然后我就根据网上的方法部署一个webservice到网站上，但是C#程序引用时还是不行。初学C#，很多都还不懂，所以不知道是哪里出了问题，希望各位大佬帮忙看看，不胜感激
这是webservice1.asmx.cs里的内容

namespace Webservice
{
    /// <summary>
    /// WebService1 的摘要说明
    /// </summary>
    [WebService(Namespace = "localhost")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消注释以下行。 
     [System.Web.Script.Services.ScriptService]
    public class WebService1 : System.Web.Services.WebService
    {

        [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

        DBOperation dbOperation = new DBOperation();
    }
}

这是类DBOperation里的内容：

 public class DBOperation : IDisposable
    {
        public static SqlConnection sqlCon;  //用于连接数据库           //将下面的引号之间的内容换成上面记录下的属性中的连接字符串         
        private String ConServerStr = @"Data Source=DAWN\MSSQLSERVER2;Initial Catalog=KYQuery;Persist Security Info=True;User ID=sa;Password=123456";         //默认构造函数         
        public DBOperation()
        {
            if (sqlCon == null)
            {
                sqlCon = new SqlConnection();
                sqlCon.ConnectionString = ConServerStr;
                sqlCon.Open();
            }
        }       
        //关闭/销毁函数，相当于Close()         
        public void Dispose()
        {
            if (sqlCon != null)
            {
                sqlCon.Close();
                sqlCon = null;
            }
        }

    }

    这是C#程序里引用webservice的内容：

ServiceReference1.WebService1SoapClient ws = new ServiceReference1.WebService1SoapClient();
            SqlConnection sqlcn = new SqlConnection();
            string connectionString = @"Data Source = DAWN\MSSQLSERVER2; Initial Catalog = KYQuery;User ID = sa; Password = 123456";
            sqlcn.ConnectionString = connectionString;
            SqlCommand sqlcm = new SqlCommand();
            sqlcm.Connection = sqlcn;
            sqlcm.CommandType = CommandType.Text;
            sqlcm.CommandText = "select * from KYQuery";
            sqlcn.Open();
            SqlDataAdapter adapter = new SqlDataAdapter();
            adapter.SelectCommand = sqlcm;
            DataSet ds = new DataSet();
            adapter.Fill(ds);
            sqlcm.Dispose();
            if (sqlcn != null)
            {
                sqlcn.Dispose();
                sqlcn.Close();
            }

            DataTable dt = ds.Tables[0];
            dataGridView1.DataSource = dt;

Answer 1

namespace Webservice
{
///
/// WebService1 的摘要说明
///
[WebService(Namespace = "localhost")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消注释以下行。
[System.Web.Script.Services.ScriptService]
public class WebService1 : System.Web.Services.WebService
{

    [WebMethod]
    public string HelloWorld()
    {
        return "Hello World";
    }

    [WebMethod]
    public DataTable Select()
    {
         DBOperation dbOperation = new DBOperation();
     SqlConnection sqlcn = new SqlConnection();
        string connectionString = @"Data Source = DAWN\MSSQLSERVER2; Initial Catalog = KYQuery;User ID = sa; Password = 123456";
        sqlcn.ConnectionString = connectionString;
        SqlCommand sqlcm = new SqlCommand();
        sqlcm.Connection = sqlcn;
        sqlcm.CommandType = CommandType.Text;
        sqlcm.CommandText = "select * from KYQuery";
        sqlcn.Open();
        SqlDataAdapter adapter = new SqlDataAdapter();
        adapter.SelectCommand = sqlcm;
        DataSet ds = new DataSet();
        adapter.Fill(ds);
        sqlcm.Dispose();
        if (sqlcn != null)
        {
            sqlcn.Dispose();
            sqlcn.Close();
        }
        return ds.Tables[0];//此处可序列化成json 返回string
    }

}

}

ServiceReference1.WebService1SoapClient ws = new ServiceReference1.WebService1SoapClient();
dataGridView1.DataSource = ws.Select();

你完全没有理解到WebService是什么。