diff --git a/AyaNovaQBI/MainForm.cs b/AyaNovaQBI/MainForm.cs
index 6ae9685..e4ba785 100644
--- a/AyaNovaQBI/MainForm.cs
+++ b/AyaNovaQBI/MainForm.cs
@@ -150,35 +150,11 @@ namespace AyaNovaQBI
 
 
 
-
-
-
-
         #region WORKORDERS / INVOICING
 
+        private async void multipleWorkordersPerInvoiceToolStripMenuItem_Click(object sender, EventArgs e) => await InvoiceSelected(false);
 
-
-        private void multipleWorkordersPerInvoiceToolStripMenuItem_Click(object sender, EventArgs e)
-        {
-            if (grid.SelectedRows.Count < 1)
-            {
-                MessageBox.Show("There are no rows selected, select one or more rows to invoice");
-                return;
-            }
-            MessageBox.Show($"STUB: MULTIPLEwoperinvoice {grid.SelectedRows.Count} rows selected");
-        }
-
-        private void oneWorkOrderPerInvoiceToolStripMenuItem_Click(object sender, EventArgs e)
-        {
-            if (grid.SelectedRows.Count < 1)
-            {
-                MessageBox.Show("There are no rows selected, select one or more rows to invoice");
-                return;
-            }
-
-            MessageBox.Show($"STUB: onwoperinvoice {grid.SelectedRows.Count} rows selected");
-
-        }
+        private async void oneWorkOrderPerInvoiceToolStripMenuItem_Click(object sender, EventArgs e) => await InvoiceSelected(true);
 
         private async void fixProblemsToolStripMenuItem_Click(object sender, EventArgs e)
         {
@@ -309,6 +285,113 @@ namespace AyaNovaQBI
 
 
 
+        /// <summary>
+        /// Invoice selected items
+        /// </summary>
+        private async Task InvoiceSelected(bool bOneWoPerInvoice)
+        {
+            if (grid.SelectedRows.Count < 1)
+            {
+                MessageBox.Show("There are no Work order rows selected\r\nSelect one or more rows to invoice");
+                return;
+            }
+
+            //An array list to hold the guid's of workorders being invoiced
+            ArrayList al = new ArrayList();
+            this.Refresh();
+            Cursor.Current = Cursors.WaitCursor;
+            ArrayList alErrors = new ArrayList();
+            Waiting w = new Waiting();
+            w.Show();
+            w.Ops = "Invoicing to QuickBooks...";
+
+            //work through selected items top to bottom
+            foreach (UltraGridRow r in grid.Selected.Rows)
+            {
+                //clear the workorder list
+                al.Clear();
+
+                //One lone workorder to be invoiced?
+                if (r.Band.Index == 1)
+                {
+                    //it's a child so see if it's parent is selected and if so then ignore it
+                    //as it will be invoiced with the parent or more likely already has been
+                    if (r.ParentRow.Selected)
+                        continue;
+
+                    //It's a stand alone single workorder selected to be invoiced on it's own
+                    //with no parent invoice row selected, so invoice it out now
+
+                    // but check to see if it's all linked first:
+                    if ((bool)r.Cells["Linked"].Value == false)
+                        continue;
+
+                    al.Add((Guid)r.Cells["WorkorderID"].Value);
+                    w.Step = "Invoicing single workorder ";
+                    Util.Invoice(al, alErrors);
+                    continue;
+
+
+                }
+                else
+                {
+                    //A group of workorders to be invoiced?
+                    if (r.Band.Index == 0 && r.Selected)
+                    {
+                        foreach (UltraGridRow rchild in r.ChildBands[0].Rows)
+                        {
+                            if ((bool)rchild.Cells["Linked"].Value == true)
+                            {
+                                al.Add((Guid)rchild.Cells["WorkorderID"].Value);
+                                //case 1604
+                                if (bOneWoPerInvoice)
+                                {
+                                    //then invoice it out now
+                                    w.Step = "Invoicing single workorder ";
+                                    Util.Invoice(al, alErrors);
+                                    //and clear al workorders list
+                                    al.Clear();
+                                }
+
+                            }
+
+                        }
+                        if (al.Count > 0)
+                        {
+                            w.Step = "Invoicing " + al.Count.ToString() + ((al.Count > 1) ? " Workorders" : " Workorder");
+                            Util.Invoice(al, alErrors);
+                        }
+
+                    }
+                }
+            }//end of foreach loop
+
+            w.Close();
+
+            //display errors if any
+            if (alErrors.Count != 0)
+            {
+
+                StringBuilder sb = new StringBuilder();
+                sb.Append("Invoicing completed with some errors:\r\n\r\n");
+                foreach (object o in alErrors)
+                {
+                    sb.Append((string)o);
+                    sb.Append("\r\n************\r\n");
+
+                }
+
+                CopyableMessageBox cb = new CopyableMessageBox(sb.ToString());
+                cb.ShowDialog();
+
+
+            }
+
+            //refresh display
+            InitInvoices();
+        }
+
+
         #endregion workorders / invoicing