Thread: Combobox problem

  1. #1
    Registered User
    Join Date
    Feb 2008

    Combobox problem

    Hello, i have a problem when filling a combobox by setting its datasource to a listArray that contains objects.

    I make objects from a class like this:

    class Teacher
            public int id;
            public string firstName;
            public string lastName;
            public Teacher(int id, string firstName, string lastName)
       = id;
                this.firstName = firstName;
                this.lastName = lastName;
    Then I have an other class where i have a function that returns me an arrayList with objects from mssql database.

    class SqlCommands
            public SqlConnection conn;
            public SqlCommands()
                conn = new SqlConnection();
                conn.ConnectionString = @"Data Source=.\SQLExpress;Integrated Security=true; AttachDbFilename=|DataDirectory|\baza.mdf;User Instance=true";   
            public ArrayList getAllTeachers()
                SqlDataReader reader = null;
                SqlCommand command = new SqlCommand("SELECT id, firstName, lastName FROM teachers", conn);
                reader = command.ExecuteReader();
                ArrayList objArray = new ArrayList();
                while (reader.Read())
                    objArray.Add(new Teacher(Convert.toInt32(reader["id"]), reader["firstName"].ToString(), reader["lastName"].ToString()));
                return objArray;
    In the main class I tried to populate the combobox like this:
    SqlCommands sql = new SqlCommands();
                ArrayList list = sql.getAllTeachers();
                cmbTeacher.DataSource = list;
                cmbTeacher.DisplayMember = "firstName";
                cmbTeacher.ValueMember = "id";
    Then i get an error like in the attachment below.

    Do anyone knows how to solve this?

    Thanks in advance

  2. #2
    Confused Magos's Avatar
    Join Date
    Sep 2001
    Perhaps id has to be a string?

    Give a man a fish and you feed him for a day.
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