How to validate if SharePoint list item update was successfull - sharepoint

Question

I am trying to update a SharePoint list through an InfoPath form. A starting date SelectedDAM is input, and the code then calculates 6 dates. Newly calculated dates have to be updated in the original SP list.
The code below raises no exception in debug mode, and even in production. I checked that 'jobs' gets populated with data, and that le list names are as per their SharePoint name. Saddly, when I look to the SharePoint list afterward, items were not updated.
public void SetDAMButton_Clicked(object sender, ClickedEventArgs e)
{
string SelectedCEC = nav.SelectSingleNode("/my:mesChamps/my:DAMSection/my:CEC", this.NamespaceManager).Value;
string SelectedDAM = nav.SelectSingleNode("/my:mesChamps/my:DAMSection/my:DAM", this.NamespaceManager).Value;
//Query all jobs and dates from SharePoint List
XmlDocument xmlDoc = new XmlDocument();
XmlNode query = xmlDoc.CreateNode(XmlNodeType.Element, "Query", "");
XmlNode viewFields = xmlDoc.CreateNode(XmlNodeType.Element, "ViewFields", "");
query.InnerXml = "<Where>" +
"<Contains><FieldRef Name='CEC'/>" +
"<Value Type='Text'>" + SelectedCEC.Trim() + "</Value></Contains>" +
"</Where>";
viewFields.InnerXml = "<FieldRef Name='ID' />" +
"<FieldRef Name='JRS_x0020_Avant' />"+ "<FieldRef Name='JRS_x0020_Pr_x00e9_vus' />"+
"<FieldRef Name='JRS_x0020_Prevus_x0020_2' />"+ "<FieldRef Name='JRS_x0020_Avant_x0020_2' />"+
"<FieldRef Name='JRS_x0020_Pr_x00e9_vus_x0020_3' />" + "<FieldRef Name='JRS_x0020_Avant_x0020_3' />";
XmlNode listItems = sp.getListService().GetListItems(SPJobsListGlobal, null, query, viewFields, "10000000", null, null);
//Extract jobs data to an internal list
List<string[]> jobs = new List<string[]>();
for (int i = 1; i != listItems.ChildNodes[1].ChildNodes.Count; i += 2)
{
string jobId = listItems.ChildNodes[1].ChildNodes[i].Attributes[0].InnerXml;
string JRSAvant = listItems.ChildNodes[1].ChildNodes[i].Attributes[1].InnerXml;
string JRSPrevus = listItems.ChildNodes[1].ChildNodes[i].Attributes[2].InnerXml;
string JRSPrevus2 = listItems.ChildNodes[1].ChildNodes[i].Attributes[3].InnerXml;
string JRSAvant2 = listItems.ChildNodes[1].ChildNodes[i].Attributes[4].InnerXml;
string JRSPrevus3 = listItems.ChildNodes[1].ChildNodes[i].Attributes[5].InnerXml;
string JRSAvant3 = listItems.ChildNodes[1].ChildNodes[i].Attributes[6].InnerXml;
jobs.Add(new string[] { jobId.Trim(), JRSAvant.Trim(), JRSPrevus.Trim(),JRSAvant2.Trim(), JRSPrevus2.Trim(), JRSAvant3.Trim(), JRSPrevus3.Trim() });
}
jobs.RemoveAt(jobs.Count - 1);
//Update each item of SharePoint list with dates calculated from new DAM
for(int i = 0; i != jobs.Count; i++)
{
XmlDocument doc = new XmlDocument();
XmlElement batch = doc.CreateElement("Batch");
batch.InnerXml = "<Method ID='1' Cmd='Update'>" +
"<Field Name='ID'>" + SecurityElement.Escape(jobs[i][0]) + "</Field>" +
"<Field Name='DateDebut'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][1])).ToString("yyyy-MM-dd")) + "</Field>" +
"<Field Name='DateFin'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][1])).AddDays(validateJRS(jobs[i][2])).ToString("yyyy-MM-dd")) + "</Field>" +
"<Field Name='Date_x0020_D_x00e9_but_x0020_2'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][3])).ToString("yyyy-MM-dd")) + "</Field>" +
"<Field Name='Date_x0020_Fin_x0020_2'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][3])).AddDays(validateJRS(jobs[i][4])).ToString("yyyy-MM-dd")) + "</Field>" +
"<Field Name='Date_x0020_D_x00e9_but_x0020_3'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][5])).ToString("yyyy-MM-dd")) + "</Field>" +
"<Field Name='Date_x0020_Fin_x0020_3'>" + SecurityElement.Escape(Convert.ToDateTime(SelectedDAM).AddDays(-validateJRS(jobs[i][5])).AddDays(validateJRS(jobs[i][6])).ToString("yyyy-MM-dd")) + "</Field>" +
"</Method>";
sp.UpdateListItems(SPJobsListGlobal, batch);
}
Why is it not working ? Is there any additionnal line I could add to confirm update.

Answer 1

To confirm the update you can check the return value of Lists.UpdateListItems, which is an XmlNode that contains the status of the update.
From MSDN:
Return value
An XMLDATA fragment in the following form that shows the status of each method block posted through the updates parameter and that can be assigned to a System.Xml.XmlNode object. For items successfully updated, a row fragment is returned with the updated row values.