Question

MySqlConnection con = new MySqlConnection("host=*;user=*;password=*;database=*;"); 
MySqlCommand cmd = new MySqlCommand("SELECT * FROM members WHERE username = '" + textBox2.Text + "' AND password = '" + textBox3.Text + "';"); 
cmd.Connection = con; 
DataTable dt = new DataTable(); 
con.Open(); 
MySqlDataReader reader = cmd.ExecuteReader(); 

if (reader.Read() != false) 
{ 
    if (reader.IsDBNull(0) == true) 
    { 
     cmd.Connection.Close(); 
     reader.Dispose(); 
     cmd.Dispose(); 
     MessageBox.Show("Oops!There was a problem!"); 
    } 
    else 
    { 
     cmd.Connection.Close(); 
     reader.Dispose(); 
     cmd.Dispose(); 
     this.Hide(); 
     Main main = new Main(); 
     main.Show(); 
     MySqlCommand cmmd = new MySqlCommand("SELECT Pain FROM members WHERE username='" + textBox2.Text + "';"); 
     cmmd.Connection = con; 
     con.Open(); 
     MySqlDataReader read = cmmd.ExecuteReader(); 
     if (read.Read()) 
     { 
      if (read.GetDecimal(0) == 1) 
      { 
       MessageBox.Show("NO"); 
       cmmd.Connection.Close(); 
       read.Dispose(); 
       cmmd.Dispose(); 
      } 
      else 
      { 
       MessageBox.Show("YES"); 
       cmmd.Connection.Close(); 
       read.Dispose(); 
       cmmd.Dispose(); 
      } 
    } 
} 
else 
{ 
    MessageBox.Show("You Login Information is incorrect!"); 
} 

나는 PAIN 열을 읽고, 메시지 NO를 표시하고 메시지 YES를 표시하기 위해 1과 같으면 0으로 설정합니다. 통증 Collumn은 INT 유형이고 8 열입니다

Answer 1

다음과 같이 시도하십시오.

using (var con = new MySqlConnection("host=*;user=*;password=*;database=*;")) 
using (var cmd = con.CreateCommand()) 
{ 
    cmd.CommandText = "SELECT username, Pain FROM members WHERE username = @UserName AND password = @Password"; 
    cmd.Parameters.AddWithValue("@UserName", textBox2.Text); 
    cmd.Parameters.AddWithValue("@Password", textBox3.Text); 

    con.Open(); 
    using (var reader = cmd.ExecuteReader()) 
    { 
     if (reader.Read()) 
     { 
      var username = reader.GetString(0); 

      if (!reader.IsDBNull(1)) 
      { 
       var pain = reader.GetInt32(1); 
       if (pain == 1) 
       { 
        MessageBox.Show("NO"); 
       } 
       else 
       { 
        MessageBox.Show("YES"); 
       } 
      } 
     } 
     else 
     { 
      MessageBox.Show("You Login Information is incorrect!"); 
     } 

    } 

}