PetaPoco update just modified records in winforms

Question

I have this code :

namespace PetaPocoTest
{
    public partial class Form1 : Form
    {
        PetaPoco.Database db = new PetaPoco.Database("PgConnection");

        IEnumerable<customers> allCustomers;


        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            allCustomers = db.Query<customers>("SELECT * FROM customers");
            mGrid.DataSource = allCustomers .ToList();            
        }

        private void saveButton_Click(object sender, EventArgs e)
        {
             foreach (var a in allCustomers)
             {
               db.Save("customers", "custumer_id", a);
             }
        }
    }
}

bat this updates all record, no matter if they are changed or not. So, my question is does anyone know how to update only changed records in petapoco ?

Answer 1

This is how I did it (eventually!) :

namespace PetaPocoTest
{
    public partial class Form1 : Form
    {
        PetaPoco.Database db = new PetaPoco.Database("PgConnection");
        Dictionary<string, int> modRows = new Dictionary<string, int>();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            bindingSource = db.Fetch<customers>("SELECT * FROM customers");
            mGrid.DataSource = bindingSource;            
        }

        private void saveButton_Click(object sender, EventArgs e)
        {
           db.BeginTransaction();

               foreach (customers c in bindingSource)
               {
                   if (modRows.ContainsKey(c.id.ToString()))
                   {
                       db.Save("customers", "id", c);
                   }
               }

           db.CompleteTransaction();
        }

        private void mGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {
            int recId = ((customers)bindingSource.Current).id;

            if (!modRows.ContainsKey(recId.ToString()))
            {
               modRows.Add(recId.ToString(), recId);
            }
        }

    }
}

It functions, but if anyone has better idea pls share!