using of the unnecessary visual studio

Question

Does anyone know why it gets like this?

It shows that using is not being used, but I do not understand why it is not recognized if I am using in the function below.

Resolution:

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using MySql.Data.MySqlClient;
    using System.Data;

    namespace MySqlServerDemo
    {
    public partial class WebForm1 : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            BindData();
        }

       public void BindData()
        {
            MySqlConnection con = new MySqlConnection("server=localhost;user    id=root;database=test");
            con.Open();

            MySqlCommand cmd = new MySqlCommand("select * from person", con);
            MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            adp.Fill(ds);

            GridView1.DataSource = ds;
            GridView1.DataBind();
            cmd.Dispose();
            con.Close();
        }  
    }
}

Answer 1

Your problem is occurring due to incorrect method creation BindData, at the completion of your method you forgot the ().

See the correct statement.

public void BindData() 
{ 
     // seu código ... 
}

Compile (click the button Build Solution) your project and fix all errors that appear, after that the references that are not actually used will be in lighter color (almost transparent) these references can be removed smoothly for the application, you can remove one by one or use the button () to remove all unused reverences and order those remaining.

Answer 2

Well, in addition to @Marconciliosouza’s reply, there are more errors in your code.

Look at these lines:

MySqlCommand = cmd = new MySqlCommand("select * from person", con);
MySqlDataAdapter = adp = new MySqlDataAdapter(cmd);

The correct statement is:

MySqlCommand cmd = new MySqlCommand("select * from person", con);
MySqlDataAdapter adp = new MySqlDataAdapter(cmd);

That is, your method BindData should stay that way:

public void BindData()
{
    MySqlConnection con = new MySqlConnection("server=localhost;user    id=root;database=test");
    con.Open();

    MySqlCommand cmd = new MySqlCommand("select * from person", con);
    MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
    DataSet ds = new DataSet();
    adp.Fill(ds);

    GridView1.DataSource = ds;
    GridView1.DataBind();
    cmd.Dispose();
    con.Close();
 } 

With these modifications, I believe it will work normally. If you have any other questions, I’m available to help.

Answer 3

Complementing the answer, the clearest "usings" theoretically are not being used and can be removed.

Theoretically because if there is a syntax error, the VS pre-compiler can mark a certain line of using as not needed when it actually is (after correction of the syntax).

It is good practice to remove excess lines to keep code cleaner.