Question

The Reader is always null, I have no idea why.

Before the connection was in one method, everything worked fine.

Code:

private MySqlConnection connection;
private MySqlCommand command;
private MySqlDataReader Reader;

public Form1()
{
    InitializeComponent();
    DBint();
}
private void DBint()
{
    string myConnectionString = "SERVER=xxx;PORT=3306;" +
                                "DATABASE=xxx;" +
                                "UID=root;" +
                                "PASSWORD=xxx;";
    connection = new MySqlConnection(myConnectionString);
    command = connection.CreateCommand();
    MySqlDataReader Reader;//error occures her
    connection.Open();
    Reader = command.ExecuteReader();               
    //MessageBox.Show(tmp);                
    //connection.Close();    
}

Answer 1

You should set the CommandText property of the command object with your SELECT statement or stored procedure name, you cannot execute an empty command.