Retrieve / Update SharePoint task Predecessors Programmatically

Let’s see how we can retrieve/Update SharePoint list task predecessors programmatically.

Here is the sample code for retrieve/Update SharePoint list task predecessors.

          Retrieve Predecessors

SPListItem item = Selectedlist.GetItemById(taskID);

SPFieldLookupValueCollection objLookupFieldValueCol = new SPFieldLookupValueCollection(item["Predecessors"].ToString());

for (int i = 0; i < objLookupFieldValueCol.Count; i++)

     {

SPFieldLookupValue singlevalue = objLookupFieldValueCol[i];

 //use singlevalue to get other details [singlevalue.LookupId ,singlevalue.LookupValue]

     }

          Update Predecessors

SPListItem itemToUpdate = Selectedlist.GetItemById(taskID);

// dtSelectedPredecessors = selected Predecessors datatable

SPFieldLookupValueCollection objLookupFieldValueCol = new SPFieldLookupValueCollection();

for (int i = 0; i < dtSelectedPredecessors.Rows.Count; i++)

    {

SPFieldLookupValue objLookupFieldValue = new SPFieldLookupValue();

objLookupFieldValue.LookupId = Convert.ToInt32(dtSelectedPredecessors.Rows[i]["itemID"].ToString());

objLookupFieldValueCol.Add(objLookupFieldValue);

    }

itemToUpdate [SPBuiltInFieldId.Predecessors] = objLookupFieldValueCol;

itemToUpdate.Update();