C#•8mo ago

Database function skipping data

Hello, when I run the below method it is supposed to return a string array with a list of users, but when I run the debugger, the reader object has rows, but it skips over the while loop. Here is the code:

C#
public static List<string> RetrieveUserList()
{
  List<string> users = new List<string>();
  
  DBConnect.StartConnection(); // used to open connection with database
  
  try
  {
    using (DBConnect.Conn) // Use open connection
    {
      string getUsers = "SELECT userName FROM client_schedule.user"; // create command string
      
      using (MySqlCommand cmd = new MySqlCommand(getUsers, DBConnect.Conn))
      {
        MySqlDataReader reader = cmd.ExecuteReader();
        
        while (reader.Read())
        {
          string temp = reader.GetString(0);

          users.Add(temp);
        }
      }
    }
  }
  catch (MySqlExeception ex)
  {
    DBConnect.StopConnection(); // close if exception occurs

    MessageBox.Show(ex.Message);
  }
  
  DBConnect.StopConnection(); // close connection

  return users;
}

C#
public static List<string> RetrieveUserList()
{
  List<string> users = new List<string>();
  
  DBConnect.StartConnection(); // used to open connection with database
  
  try
  {
    using (DBConnect.Conn) // Use open connection
    {
      string getUsers = "SELECT userName FROM client_schedule.user"; // create command string
      
      using (MySqlCommand cmd = new MySqlCommand(getUsers, DBConnect.Conn))
      {
        MySqlDataReader reader = cmd.ExecuteReader();
        
        while (reader.Read())
        {
          string temp = reader.GetString(0);

          users.Add(temp);
        }
      }
    }
  }
  catch (MySqlExeception ex)
  {
    DBConnect.StopConnection(); // close if exception occurs

    MessageBox.Show(ex.Message);
  }
  
  DBConnect.StopConnection(); // close connection

  return users;
}

4 Replies

Jimmacle•8mo ago

.Append doesn't modify the source array you want to use a List<string> instead and call .Add this code doesn't look like it should compile at all, you declare string[] user = null; then try to append to something called users

XantresOP•8mo ago

Sorry, I miss typed the variable, it is users

Jimmacle•8mo ago

so you have 2 issues the one i mentioned, and trying to call methods on a null reference

XantresOP•8mo ago

I am working on this for a school project and have to use a virtual machine so I can't copy code from it to my machine Okay, so I have changed the above to what I have and that worked, thanks for your direction.

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Database function skipping data