Unable to modifiy the Folder custom column inside my CSOM

Question

I have the following code inside my CSOM:-

Folder folder = context.Web.GetFolderByServerRelativeUrl(context.Web.ServerRelativeUrl + "/library3/" + currentFilingSystemItem["DealName"].ToString());
context.ExecuteQuery();

currentFilingSystemItem["DealStage"] =  "7178cede-c689-4b47-853a-88bb8b95e230";;
currentFilingSystemItem.Update();
folder.ListItemAllFields["DealStage"] = "7178cede-c689-4b47-853a-88bb8b95e230";
folder.Update();
context.ExecuteQuery();

the above code will update the list item currentFilingSystemItem DealStage value but will not update the folder DealStage value. the DealStage is a managed metadata coumn which alllow single selection. Any advice?

Regards

Answer 1

folder.ListItemAllFields return ListItem object which you need to update not the folder object. Try following way to update.

ListItem item = folder.ListItemAllFields;
item["DealStage"] = "7178cede-c689-4b47-853a-88bb8b95e230";
item.Update();

Answer 2

The primary problem is that you are calling Update() on the folder, when you need to call it on the ListItemAllFields property:

folder.ListItemAllFields["DealStage"] = "7178cede-c689-4b47-853a-88bb8b95e230";
folder.ListItemAllFields.Update();
context.ExecuteQuery();

But, secondarily, you should use TaxonomyFieldValue (for single-value managed metadata columns) and TaxonomyFieldValueCollection (for multi-value managed metadata columns). If your currentFilingSystemItem, then you may have gotten lucky, in most cases, setting a taxonomy field to a raw guid will not update the value correctly. Also note the use of the SetFieldValueByValue method on the actual Field object, rather than simply setting the field equal to a value. Taxonomy fields are considerably more difficult to code updates for than scalar value fields are. Your code should look more like this:

Folder folder = context.Web.GetFolderByServerRelativeUrl(context.Web.ServerRelativeUrl + "/library3/" + currentFilingSystemItem["DealName"].ToString());
context.Load(folder);
var folderListItem = folder.ListItemAllFields;
context.Load(folderListItem);
var dealStageField = list.Fields.GetByInternalNameOrTitle("DealStage");
context.Load(dealStageField);
context.ExecuteQuery();

var dealStageTaxField = context.CastTo<TaxonomyField>(field);
var dealStageTermValue = new TaxonomyFieldValue();
//dealStageTermValue.Label = "Display Text from the Term"; // Note that if you do not set this value, or you set it to a value that doesn't match what is in the termstore, the value may display incorrectly in list views for several minutes before SharePoint synchronizes from the termstore.
dealStageTermValue.TermGuid = new Guid("7178cede-c689-4b47-853a-88bb8b95e230");
dealStageTermValue.WssId = -1;

dealStageTaxField.SetFieldValueByValue(currentFilingSystemItem, dealStageTermValue);
currentFilingSystemItem.Update();

dealStageTaxField.SetFieldValueByValue(folderListItem, dealStageTermValue);
folderListItem.Update();

context.ExecuteQuery();