c# - using UDF in datatable for datagridview

I am passing a DataTable object into a Windows Form and
binding the DataTable to a DataGridView. In the DataGridView I allow a user to edit and
add data / rows. I need to display the results of two calculations on the DataGridView
depending on the data that the user enters. The calculations are results of 2 methods
that get called from events on the DataGridView. Those work great during an active edit
or use of the DataGridView.
After a user saves the items I return the
DataTable object to a class that saves the data to the underlying table.

The problem I have is when a user opens the
Windows Form again to edit a record, my calculations do not show because events have not
been fired on the DataGridView that would trigger the respective
methods.

So, I was thinking that I could send
the calculated fields along with the DataTable object, or I need to hook the calculation
methods to more events in the Windows Form /
DataGridView.

If I send the calculated fields
along with the DataTable, that would cause issues with returning the DataTable object
for the database update actions
right?

I would appreciate thoughts
and / or suggestions.
Thanks

I can
post any relevant code if it
helps.

*this code
handles data changes in the grid view
cells*

private
            void datagridWorkorderPartItems_CellValueChanged(object sender,
            DataGridViewCellEventArgs e)
{

 int ID;

            HighlightSaveItems();
 DataGridViewRow row =
            this.datagridWorkorderPartItems.Rows[e.RowIndex];
 DataGridViewCell cell =
            row.Cells[e.ColumnIndex];
 if (!DBNull.Value.Equals(row.Cells[3].Value)
            && !DBNull.Value.Equals(row.Cells[2].Value))
 {
 if
            (e.ColumnIndex == 2 || e.ColumnIndex == 3)
 {
 decimal
            price;
 decimal originalprice;

 decimal
            partmargin;
 Pricing p = new Pricing();
 ID =
            Convert.ToInt32(row.Cells[3].Value);

 //if price all ready has a
            value or has been altered, don't change it
 price =
            p.GetPartItemPrice(ID);
 originalprice = price;
 Parts part = new
            Parts();
 partmargin = part.LookupPartMargin(ID);
 //now take the
            price and check against customer price level

 decimal
            pricelevel;
 decimal invertedpricelevel;
 string level;

            Customers c = new Customers();
 level =
            c.GetCustomerPartsLevel(_cid);
 Options o = new Options();

            pricelevel = o.GetPartsLevelPercent(level);

 //get proper percent -
            100
 if (pricelevel == 1)

 {

            invertedpricelevel = 1;
 }
 else
 {

            invertedpricelevel = 1 - pricelevel; //inverted the percent

            }

 price = price *
            invertedpricelevel;


 try
 {
 if
            (e.ColumnIndex == 3) //column 3 is part id
 {
 if
            (row.Cells[2].Value == null || row.Cells[2].Value == "0") //qty is null or 0

            {
 row.Cells[2].Value = "1"; //set it to assume 1
 if
            (row.Cells[4].Value == null)
 {
 row.Cells[4].Value = price * 1;
            //assume the price is price * 1

 row.Cells[5].Value =
            originalprice;
 row.Cells[6].Value = partmargin.ToString("P");

            }
 }
 else
 {
 row.Cells[4].Value = price *
            Convert.ToInt32(row.Cells[2].Value);
 row.Cells[5].Value =
            originalprice;
 row.Cells[6].Value = partmargin.ToString("P");

            }

 }
 else if (e.ColumnIndex == 2)

            {
 if (row.Cells[4].Value == null)
 {
 row.Cells[4].Value
            = "0";
 row.Cells[5].Value = "0";
 row.Cells[6].Value =
            "0";
 }
 else

 {
 row.Cells[4].Value
            = price * Convert.ToInt32(row.Cells[2].Value);
 row.Cells[5].Value =
            originalprice;
 row.Cells[6].Value = partmargin.ToString("P");

            }
 }
 }
 catch (Exception m)
 {

            MessageBox.Show("Error: " + m.Message.ToString() + " Source: " + m.Source.ToString() + "
            " + m.InnerException.ToString(), "Error", MessageBoxButtons.OK,
            MessageBoxIcon.Exclamation);

 }

            }

*This
code gets the data table I am working
on*

public
            DataTable WorkorderPartItemsTable(int WOID)
{
 ConfigDAL config =
            new ConfigDAL();
 string connstr =
            config.GetConnString();

 SqlConnection conn = new
            SqlConnection(connstr);
 string query;
 Parts part = new
            Parts();

 query = "SELECT * FROM WorkorderItems WHERE (WorkorderID
            = @WorkorderID) AND (PartID <> '0')";
 SqlDataAdapter da = new
            SqlDataAdapter();
 da.SelectCommand = new SqlCommand(query, conn);

            da.SelectCommand.Parameters.AddWithValue("@WorkorderID", WOID);
 DataTable dt
            = new DataTable();
 conn.Open();

 da.Fill(dt);

            conn.Close();
 return
            dt;
}

p.GetPartItemPrice(ID)
and part.LookupPartMargin(ID) are the 2 values that are calculated when ever a change is
made to a column in the datagridview. THose do not get calculated when I load the
form.