如何编写Web服务以将MySQL连接到Windows应用商店？

Question

I have developed a Windows store app in C# and I have a MySQL database(workbench) that provides data for the store app. I have connected these directly without any web service. But now I want to introduce a web service between them. I have developed the store app using Visual studio 2012. I have no ides on how a web service looks like or where it is written. I browsed a lot through the web. I have just a vague idea that I have to write this web service and consume it in my store app. But it is not clear on where to write and how to write.

I have only got samples for the SQL server which is not helpful for me. Can anyone provide me proper directions and steps as to how to write this web service, Where to write it and How to access it in my Windows store app?

This is what I tried out in my service1.asmx.cs file:

namespace WebService1 {

/// <summary>
/// Summary description for Service1
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
// [System.Web.Script.Services.ScriptService]

public class Service1 : System.Web.Services.WebService
{
    [WebMethod]
    public DataSet GetStudents()
{
     using (MySqlConnection connection = new MySqlConnection 
     (ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString))
     {
         string Query = "SELECT * FROM [student]";
         MySqlCommand command = new MySqlCommand(Query, connection);
         command.CommandType = CommandType.Text;           
         connection.Open();
         MySqlDataReader reader = command.ExecuteReader();

         DataTable StuTable = new DataTable("student");
         StuTable.Columns.Add("id", typeof(string));
         StuTable.Columns.Add("password", typeof(string));
         StuTable.Columns.Add("courseid", typeof(string));           

        while (reader.Read())
        {
             StuTable.Rows.Add(new object[]
             {
                  reader["id"].ToString(), reader["password"].ToString(), 
                  reader["courseid"].ToString()});
             }

             StuTable.AcceptChanges();
             DataSet ds = new DataSet();
             ds.Tables.Add(StuTable);
             ds.AcceptChanges();
             return ds;
        }
}


}

}

But I had no idea how to use this in my Store app.

Answer 1

Web service is just some dynamically generated data(sql-query response in your case), that can be accessed or altered via standalone web-request to remote server from client application and in some rare cases just by user in browser window. It can be very strict and standardized(like SOAP), little restricted(like REST), or not restricted in any way(as most of user-made API).

As first step, you must define to yourself what kind of actions your web service must do - the methods of your service, and what they must(if needed) return.

At second step you need to implement this "methods" on real web-server using any of programming language where you do requests to real database(select's, updates, insert's and so on..). You not restricted in any way - you can write web-service in node.js or php, python or whatever else, service can be placed on server working under Windows, Linux, or be "in cloud" - is totally fine.

At third step you must replace methods that you want to separate from client-part with stubs that will make requests to your "web-service" placed on some remote web-server.

Basically, this is all magic about this scary "web-service" thing. Easy isn't? It's more just "marketing word" than some "new awesome revolutionary piece of technology" :)

But writing big web-service just from scratch may be hard and very boring, so there are many pieces of code that written by companies and individuals in purpose to abstract and simplify process of implementing web services... Namespace System.Web.Services in .NET Framework - is one of this pieces, where "web-service" is just a public class that based on System.Web.Services.WebService, in which can be placed public methods with [WebMethod] attribute. Just make and write new project from Visual Studio "Web Service" template - it's fun and easy :)