CS0103 C# The name does not exist in the current context RSS

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  Teck Loong

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  CS0103 C# The name does not exist in the current context

  Feb 14, 2021 02:24 PM|Teck Loong|LINK

  <div>Hello everyone, I am not sure why am I getting the name 'listID' does now exist in the current context. As I am still new to ASP.NET, any help would be greatly appreciated! Thanks!</div> <div></div> <div></div> <div>

  
  
  
  
  my aspx.cs file
  
  
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Data;
  using System.Data.SqlClient;
  using System.Configuration;
  
  
  namespace CustomerHandyApplication
  {
  public partial class ServiceView : System.Web.UI.Page
  {
  // create a new class by initializing service
  ServiceInfo aService = new ServiceInfo();
  ServiceInfo bService = new ServiceInfo();
  ServiceInfo list = new ServiceInfo();
  
  
  protected void Page_Load(object sender, EventArgs e)
  {
  // create instance where ServiceInfo = a
  ServiceInfo a = new ServiceInfo();
  List listingsService = new List ();
  
  
  if (!IsPostBack)
  {
  //store the list of ServiceNo into the nameList
  List nameList = a.getListingNameAll();
  List handyService = listingsService;
  }
  }
  
  
  // bind the details in the grid view together
  // create a new class ServiceList
  protected void bind()
  {
  List serviceData = new List();
  serviceData = aService.getServiceInfoAll();
  gvService.DataSource = serviceData;
  gvService.DataBind();
  
  
  List serviceList = new List();
  serviceList = bService.getListingNameAll();
  gvService.DataSource = serviceList;
  gvService.DataBind();
  
  
  List listingsService = new List();
  listingsService = list.getListings(listID);
  gvService.DataSource = listingsService;
  gvService.DataBind();
  }
  
  
  protected void gvService_SelectedIndexChanged(object sender, EventArgs e)
  {
  // Get the currently selected row
  // Display by the row
  GridViewRow row = gvService.SelectedRow;
  
  
  // Get Listing_Name from the selected row,
  // which is the first row, i.e. index 0
  string listName = row.Cells[0].Text;
  decimal price = decimal.Parse(row.Cells[1].Text);
  string handyName = row.Cells[2].Text;
  
  
  Response.Redirect("Pre-BookAppointment.aspx");
  }
  
  
  protected void ddl_List_SelectedIndexChanged(object sender, EventArgs e)
  {
  string listID = ddl_List.SelectedValue;
  Response.Redirect("ViewService.aspx?ListID=" + listID);
  bind();
  }
  }
  }
  
  
  //my cs file:
  
  
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Data.SqlClient;
  using System.Configuration;
  using System.Data;
  
  
  namespace CustomerHandyApplication
  {
  public class ServiceInfo
  {
  //Private string _connStr = Properties.Settings.Default.DBConnStr;
  // set the values to each of the attributes
  //System.Configuration.ConnectionStringSettings _connStr;
  string _connStr = ConfigurationManager.ConnectionStrings["CustomerContext"].ConnectionString;
  
  
  // private attributes of attributes in the database table
  private string _listID = "";
  private string _listName = "";
  private decimal _price = 0;
  private string _handyName = "";
  
  
  
  
  // Default constructor
  public ServiceInfo()
  {
  }
  
  
  // Constructor that take in all data required to build a ServiceInfo object
  // ServiceInfo class that takes 3 arguments
  // set the attributes to each of the variables by making it private
  public ServiceInfo(string listID, string listName, decimal price, string handyName)
  {
  _listID = listID;
  _listName = listName;
  _price = price;
  _handyName = handyName;
  }
  
  
  // Constructor that take in all except Listing_ID
  // create all variables as the attributes
  // ID – unique key of service = Listing_ID
  // auto constructor: it generates an auto listName from the database to access to all the attributes of the ServiceInfo table.
  // Hence it does not pass in the service_No, but the rest of the attributes in the table unless it is specified by the rules of the company.
  
  
  public ServiceInfo(string listName, decimal price, string handyName)
  : this("", "", price, handyName)
  {
  }
  
  
  // Constructor that take in only Listing_ID. The other attributes will be set to 0 or empty.
  public ServiceInfo(string listID)
  : this(listID, "", 0, "")
  {
  }
  
  
  // set the attributes under the object
  // by creating the class instances of each attributes in the object
  // create the Get/Set the attributes of the Product object.
  // Note the attribute name (e.g. Listing_Name) is same as the actual database field name.
  // This is for ease of referencing.
  
  
  public string Listing_ID
  {
  get
  {
  return _listID;
  }
  set
  {
  _listID = value;
  }
  }
  
  
  public string Listing_Name
  {
  get
  {
  return _listName;
  }
  set
  {
  _listName = value;
  }
  }
  
  
  public decimal Price
  {
  get
  {
  return _price;
  }
  set
  {
  _price = value;
  }
  }
  
  
  public string Handyman_Name
  {
  get
  {
  return _handyName;
  }
  set
  {
  _handyName = value;
  }
  }
  
  
  //Below as the Class methods for some DB operations.
  // getServiceInfo(Listing_Name) - to retrieve listName data from the gvService
  public ServiceInfo getSeviceInfo(string listID)
  {
  ServiceInfo handylistDetail = null;
  string list_Name,handy_Name;
  decimal price;
  
  
  // query the attributes by selecting each of the attributes in the CustomerContext database
  string queryStr = "SELECT * FROM Lisitngs WHERE Listing_ID = @ListID ";
  
  
  // request the connection by getting the database of the attributes from the CustomerContext database using the connStr variable
  SqlConnection conn = new SqlConnection(_connStr);
  SqlCommand cmd = new SqlCommand(queryStr, conn);
  cmd.Parameters.AddWithValue("@ListID", listID);
  
  
  // open the connection by starting to read and execute each of the attibutes in the CustomerContext database
  conn.Open();
  SqlDataReader dr = cmd.ExecuteReader();
  
  
  // read each of the attributes in the CustomerContext in the string format
  // exclude listID which is primary key
  if (dr.Read())
  {
  list_Name = dr["Listing_Name"].ToString();
  price = decimal.Parse(dr["Price"].ToString());
  handy_Name = dr["Handyman_Name"].ToString();
  
  
  handylistDetail = new ServiceInfo(listID, list_Name, price, handy_Name);
  }
  else
  {
  handylistDetail = null;
  }
  
  
  conn.Close();
  dr.Close();
  dr.Dispose();
  
  
  return handylistDetail;
  } //end of retrieve
  
  
  // getServiceInfoAll()-to retrieve all the data from the gvService
  public List getServiceInfoAll()
  {
  List handyList = new List();
  
  
  // include listName which is a primary key
  string list_ID, list_Name, handy_Name;
  decimal price;
  
  
  string queryStr = "SELECT * FROM Listings";
  
  
  SqlConnection conn = new SqlConnection(_connStr);
  SqlCommand cmd = new SqlCommand(queryStr, conn);
  
  
  conn.Open();
  SqlDataReader dr = cmd.ExecuteReader();
  
  
  // include listName which is a primary key
  while (dr.Read())
  {
  list_ID = dr["Listing_ID"].ToString();
  list_Name = dr["Listing_Name"].ToString();
  price = decimal.Parse(dr["Price"].ToString());
  handy_Name = dr["Handyman_Name"].ToString();
  
  
  ServiceInfo a = new ServiceInfo(list_ID, list_Name, price, handy_Name);
  handyList.Add(a);
  }
  
  
  conn.Close();
  dr.Close();
  dr.Dispose();
  
  
  return handyList;
  }
  
  
  //getListingNameAll() - to retrieve all the data from the ddl_List
  public List getListingNameAll()
  {
  List nameList = new List();
  
  
  string list_ID, list_Name, handy_Name;
  decimal price;
  
  
  string queryStr = "SELECT * FROM Listings";
  
  
  SqlConnection conn = new SqlConnection(_connStr);
  SqlCommand cmd = new SqlCommand(queryStr, conn);
  
  
  conn.Open();
  SqlDataReader dr = cmd.ExecuteReader();
  
  
  // include listID and servNo which are primary keys
  while (dr.Read())
  {
  list_ID = dr["Listing_ID"].ToString();
  list_Name = dr["Listing_Name"].ToString();
  price = decimal.Parse(dr["Price"].ToString());
  handy_Name = dr["Handyman_Name"].ToString();
  
  
  ServiceInfo a = new ServiceInfo(list_ID, list_Name, price, handy_Name);
  nameList.Add(a);
  }
  
  
  conn.Close();
  dr.Close();
  dr.Dispose();
  
  
  return nameList;
  }
  
  
  
  
  //getListings() - to get the listID from the ddl_List
  public ServiceInfo getListings(string listID)
  {
  ServiceInfo handyService = null;
  string list_Name, handy_Name;
  decimal price;
  
  
  // query the attributes by selecting each of the attributes in the CustomerContext database
  string queryStr = "SELECT * FROM Lisitngs WHERE Listing_ID = @ListID ";
  
  
  // request the connection by getting the database of the attributes from the CustomerContext database using the connStr variable
  SqlConnection conn = new SqlConnection(_connStr);
  SqlCommand cmd = new SqlCommand(queryStr, conn);
  cmd.Parameters.AddWithValue("@ListID", listID);
  
  
  // open the connection by starting to read and execute each of the attibutes in the CustomerContext database
  conn.Open();
  SqlDataReader dr = cmd.ExecuteReader();
  
  
  // read each of the attributes in the CustomerContext in the string format
  // exclude listID which is primary key
  if (dr.Read())
  {
  list_Name = dr["Listing_ID"].ToString();
  price = decimal.Parse(dr["Price"].ToString());
  handy_Name = dr["Handyman_Name"].ToString();
  
  
  handyService = new ServiceInfo(listID, list_Name, price, handy_Name);
  }
  else
  {
  handyService = null;
  }
  
  
  conn.Close();
  dr.Close();
  dr.Dispose();
  
  
  return handyService;
  } //end of retrieve

  </div>
• • Reply
  yij sun

  Contributor

  3730 Points

  1412 Posts

  Re: CS0103 C# The name does not exist in the current context

  Feb 15, 2021 04:00 AM|yij sun|LINK

  Hi Teck Loong,

  According to your codes,I have created a test and I find "listID" is a parameter of getListings() method. So you need to define the "listID". Just like this:

  protected void bind()
          {
              
              List<ServiceInfo> serviceData = new List<ServiceInfo>();
              serviceData = aService.getServiceInfoAll();
              gvService.DataSource = serviceData;
              gvService.DataBind();
              List<ServiceInfo> serviceList = new List<ServiceInfo>();
              serviceList = bService.getListingNameAll();
              gvService.DataSource = serviceList;
              gvService.DataBind();
              List<ServiceInfo> listingsService = new List<ServiceInfo>();
              string listID = "";
              listingsService.Add(list.getListings(listID));
              gvService.DataSource = listingsService;
              gvService.DataBind();
          }

  By the way, please use {;} to post your codes to make it as a code format.

  Best regards,

  Yijing Sun

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• • Reply
  PatriceSc

  All-Star

  48490 Points

  18071 Posts

  Re: CS0103 C# The name does not exist in the current context

  Feb 15, 2021 10:29 AM|PatriceSc|LINK

  Hi,

  You have a  {;} button in the edit bar so that you can include code in a much more legible way. See https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-messages/cs0103

  It means that you are trying to use an identifier which is not declared. The actual name should be part of the error message.