Parser Error Message: Could not create type 'WebService.asmx.cs'

I am following this tutorial to create dynamic search results from an SQL server as a user types. It is telling me to create a .asmx file, which is not a format I have ever worked with before. I now have a .asmx and .asmx.cs file. Here is the code I have thus far :

WebService.asmx.cs :

public class SearchService : WebService
{
  [WebMethod]
  public searchResult[] Search(string txtSearch)
  {
//Declare collection of searchResult
        List resultList = new List();
        var db = Database.Open("mPlan");
        var result = db.Query("SELECT * from Users where Username like '%" + txtSearch + "%'");
       try
       {
           foreach(var record in result)
            {
               searchResult result = new searchResult();
               result.Username = ["Username"].ToString();
               resultList.Add(result);
           }
           return resultList.ToArray();
       }
       catch
       {
           return null;
       }
  }}

WebService.asmx :

<%@ WebService Language="C#" class="WebService" %>
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.Services;
using System.Data.SqlClient;

[System.Web.Script.Services.ScriptService]
[System.Web.Script.Services.GenerateScriptType(typeof(searchResult))]
public class searchResult
{
    public string Title;
    public string img;
    public string href;
}

Here is my error message, can anyone help me with this please?

Parser Error Message: Could not create type 'WebService.asmx.cs'

It highlights line 1 of WebService.asmx as the source of the error.