C# Cannot convert string to int error when im not even trying to convert it to int

Question

Hello can someone please help me? when i am trying to get a string value from a table on my sql server database table it says that i can not convert string to int, but i dont want to convert the value to int. as the values in the table are "Admin" and "General User".

by the way i am using sql server 2014

the variable that i use to capture the string is cap and i declared it as a string.

and when i write the code.

conn.Open();

        string query_inicio = "select * from usuarios where USU_Usuario = '" + txtusuario.Text + "' AND USU_Contra ='" + txtcontra.Text + "'";
        SqlCommand exe_query_inicio = new SqlCommand(query_inicio, conn);

        SqlDataReader leer_exe;


        try
        {



            leer_exe = exe_query_inicio.ExecuteReader();

            if (leer_exe.Read())
            {
                cap = leer_exe.GetString("Admin");

                MessageBox.Show("CONECTADO");
                if (cap.Equals("Admin"))
                {
                    Reporte_Detallado IB = new Reporte_Detallado();
                    IB.Show(this);

                    this.Hide();
                }
            }
            else if (leer_exe.Read() == false)
            {

              MessageBox.Show("Inicio Fallido, Verifique Conexion");

       }

it underlines the cap = leer_exe.GetString("Admin"); and says that i can't convert string to int.

i have the same code using a mysql datbase and it works. now i am trying to do it with microsoft sql server. so the only thing i changed from the mysql version was instead of mysqlconection and those database code lines to sqlconnection and the other variations.

here is my complete code. i hope someone can help me.

by the way i am coding in c#.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace ClimateReports
{
public partial class Login : Form
{
   SqlConnection  conn = ConexionBD.ObtenerConexion();
    string cap;

    public Login()
    {
        InitializeComponent();
    }

    private void btncancelar_Click(object sender, EventArgs e)
    {
        this.Dispose();
    }

    private void btniniciar_Click(object sender, EventArgs e)
    {
        conn.Open();
        string query_inicio = "select * from usuarios where USU_Usuario = '" + txtusuario.Text + "' AND USU_Contra ='" + txtcontra.Text + "'";
        SqlCommand exe_query_inicio = new SqlCommand(query_inicio, conn);
        SqlDataReader leer_exe;
        try
        {
            leer_exe = exe_query_inicio.ExecuteReader();               
            if (leer_exe.Read())
            {
                cap = leer_exe.GetSqlString("Admin");

                MessageBox.Show("CONECTADO");
                if (cap.Equals("Admin"))
                {
                    Reporte_Detallado IB = new Reporte_Detallado();
                    IB.Show(this);

                    this.Hide();
                }
            }
            else if (leer_exe.Read() == false)
            {

              MessageBox.Show("Inicio Fallido, Verifique Conexion");
       }

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
        conn.Close();
    }
}
}

ARGH! Use parameters. Never blindly add user data to your query string. Don't you know about Bobby Tables? — itsme86
– itsme86, Commented Mar 20, 2017 at 23:28
not really, but i will look into it. at university that a go here in mexico they dont teach alot of things. but i will look it up. and about the parameters i do know but i was a bit lazy lol — VesuvianMetal
– VesuvianMetal, Commented Mar 20, 2017 at 23:31

John Wu · Accepted Answer · 2017-03-20 23:28:25Z

4

The problem is this line:

cap = leer_exe.GetString("Admin");

GetString takes an int32 as its argument.

If you want to access a column by its name, you should use Item instead:

cap = leer_exe["Admin"] as string;

Or, if you know what column "Admin" is, you can replace it with its position index. If it's the 4th column in the resultset, you'd use index 3 (because it's base 0):

cap = leer_exe.GetString(3);

answered Mar 20, 2017 at 23:28

John Wu

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1 Comment

VesuvianMetal Over a year ago

fisrt used the cap = leer_exe["Admin"] as string; and it didnt work but the cap = leer_exe.GetString(3); work perfectly. only that for me it was 6 instead of 3. thank you very much Jonh. i really apreciate it.

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