C#

private void DataController()
{
    try
    {
        //this methods loads the data from the database into two DataTables: patientTable, doctorTable
        this.LoadData_Controller();
        
        this.FormatDataGridView();

        dgvPatients.DataSource = patientTable;
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

/// <summary>
/// adds a DataGridViewComboBoxColumn to the DataGridView and set the DataSource
/// </summary>
private void FormatDataGridView()
{
    try
    {
        #region Format Doctor column

        //create combobox column for doctors
        DataGridViewComboBoxColumn comboboxColumnDoctors = new DataGridViewComboBoxColumn();
        comboboxColumnDoctors.DataPropertyName = "Doctor";
        comboboxColumnDoctors.HeaderText = "Doctor";

        //add data to new comboboxcolumn
        comboboxColumnDoctors.DataSource = doctorTable;
        comboboxColumnDoctors.ValueMember = "Doctor_ID";
        comboboxColumnDoctors.DisplayMember = "DrName";

        //insert column into datagridview
        dgvPatients.Columns.Insert(3, comboboxColumnDoctors);

        #endregion
    }
    catch (Exception ex)
    {
        throw ex;
    }
}