title: The data types text and varchar are incompatible in the equal to operator
body: <p>I am trying to access all the records from database on a data grid view depending upon the type of user logging in through a form having 2 text-boxes for user_name and password respectively and on submit button records are displayed. But the code I have written is giving me the following error: The data types text and varchar are incompatible in the equal to operator. Please suggest changes.</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Windows.Forms;
  using System.Configuration;
  using System.Data.SqlClient;
  
  
  namespace Login_form
  {
      public partial class Form1 : Form
      {
          public Form1()
          {
              InitializeComponent();
          }
  
          private void Form1_Load(object sender, EventArgs e)
          {
  
  
  
          }
  
          private void button1_Click(object sender, EventArgs e)
          {
  
              string str = ConfigurationSettings.AppSettings["constring"].ToString();
              SqlConnection sqlcon = new SqlConnection(str);
  
  
              try
              {
                  sqlcon.Open();
              }
              catch (Exception ex)
              {
                  Console.WriteLine(ex.ToString());
              }
  
  
              SqlCommand sqlcmd = new SqlCommand("select user_type from employee where user_name='" + textBox1.Text + "'and pwd= '" + textBox2.Text + "' ;", sqlcon);
  
  
              SqlDataReader myReader = sqlcmd.ExecuteReader();
  
              string user_type=string.Empty;
  
              while(myReader.Read())
              {
              user_type= myReader["user_type"].ToString();
              }
  
              sqlcon.Close();
  
  
  
              sqlcon.Open();
              SqlCommand sqlcmd2 = new SqlCommand("select * from employee where user_type= '" +user_type + "'", sqlcon);
              SqlDataReader myReader2 = sqlcmd2.ExecuteReader();
  
            /*  SqlDataAdapter sqladapter = new SqlDataAdapter(sqlcmd2);
              DataSet ds = new DataSet();
              sqladapter.Fill(ds);
              dataGridView1.DataSource = ds.Tables[0];*/
  
              DataTable dt = new DataTable();
              dt.Columns.Add("ID", typeof(string));
              dt.Columns.Add("Name", typeof(string));
              dt.Columns.Add("Email_ID", typeof(string));
              dt.Columns.Add("Contact", typeof(string));
              dt.Columns.Add("Address", typeof(string));
  
              while (myReader2.Read())
              {
                  DataRow dr = dt.NewRow();
                  dr["ID"] = myReader2["ID"];
                  dr["Name"] = myReader2["user_name"];
                  dr["Email_ID"] = myReader2["Email_ID"];
                  dr["Contact"] = myReader2["Contact"];
                  dr["Address"] = myReader2["Address"];
                  dt.Rows.Add(dr);
              }
  
  
              dataGridView1.DataSource = dt;
  
  
              sqlcon.Close();
          }
  
      }
  }
  </code></pre>