Update a UserMulti Column value in Client Object Model C#

Update the value of User/UserMulti column in SharePoint using Client Object Model
ClientContext ctx = new ClientContext(weburl);
ctx.Credentials = new SharePointOnlineCredentials(userName, passWord); 

List list = ctx.Web.Lists.GetByTitle("ListTitle");
ListItem currentItem = list.GetItemById(1);

FieldUserValue[] userValueCollection = new FieldUserValue[1];

//Get all the users of this Web
UserCollection userCollection = this.ctx.Web.SiteUsers; 
this.ctx.Load(userCollection, w => w.Include(p => p.Id, p => p.Title));
this.ctx.ExecuteQuery(this.ctx);

User user = userCollection.FirstOrDefault(p => p.Title.ToLower().Trim() == userTitle.ToLower().Trim());

//Making sure that a user of title userTitle is present in this Web
if (user != null)
{
    FieldUserValue fieldUserVal = new FieldUserValue();
    fieldUserVal.LookupId = user.Id;
    userValueCollection.SetValue(fieldUserVal, 0);
}

currentItem["MultiUserValCol"] = userValueCollection;
currentItem.Update(); 
this.ctx.ExecuteQuery(); 

As you can see that updating a multiUser column is along the same line as updating a LookupMulti column. Hence, there are a couple of things that one should take care of while updating this column. Those are mentioned in my previous blog where I have discussed about updating a LookupMulti column. here. https://realmpksharepoint.wordpress.com/2014/01/19/update-a-lookupmulti-column-value-in-sharepoint-using-client-object-model-c/

Update a LookupMulti Column value in SharePoint using Client Object Model C#

Update the value of LookupMulti column in SharePoint using the Client Object Model
ClientContext ctx = new ClientContext(weburl);
ctx.Credentials = new SharePointOnlineCredentials(userName, passWord); 

List list = ctx.Web.Lists.GetByTitle("ListTitle");
ListItem currentItem = list.GetItemById(1);

FieldLookupValue[] lookupFieldValCollection = new FieldLookupValue[3];FieldLookupValue lookupFieldA = new FieldLookupValue();
lookupFieldA.LookupId = 2;
lookupFieldValCollection.SetValue(lookupFieldA, 0);
FieldLookupValue lookupFieldB = new FieldLookupValue();
lookupFieldB.LookupId = 4;
lookupFieldValCollection.SetValue(lookupFieldB, 1);
FieldLookupValue lookupFieldC = new FieldLookupValue();
lookupFieldC.LookupId = 6;
lookupFieldValCollection.SetValue(lookupFieldC, 2);

currentItem["MultiLookupValCol"] = lookupFieldValCollection;
currentItem.Update();

ctx.ExecuteQuery();  

Two important thing I would like to share here,

  • Initially I tried to pass an array of an array of integer [containing the ids of the item] to the LookupMulti column which generated the error: Value does not fall between the specified range
  • Another thing was then I created a List of type FieldLookupValue and then I passed the List to the column using its ToArray(). I guess we just had to pass the array of FieldLookupValue. However, this resulted in the error: Unknown Error. Don’t know what that means.

Finally, I can say that create the array of type FieldLookupValue and populate this array using its SetValue method only.

Update a LookupField value for a SharePoint ListItem using Client Object Model C#

A lookup data in a SharePoint can be treated as a choice options that has been maintained in a different List. Hence if one of your field in your List is a lookup then, its value should be the ID[integer] the actual Lookup-Item (i.e., the list item id of the List as a LookUp).

For ex, in a blog site, List, Category has been used as lookup field for the List Post. By default, in SP2013, you’ll get three items for Categories. Say, their Ids are 1,2, & 3.

  • Events[1]
  • Ideas[2]
  • Opinions[3]
Now if you want to change the Category field of a Post, then, you have to pass the ID of the item and not the text value.

ClientContext ctx = new ClientContext(targetURL);
ctx.Credentials = new SharePointOnlineCredentials(userName, passWord);

this.ctx.Load(this.ctx.Web);
SP.ListCollection listCol = web.Lists;
ctx.Load(listCol);

SP.List list = listCollection.GetByTitle("ListTitle");

SP.CamlQuery camlQuery = new SP.CamlQuery();
camlQuery.ViewXml = "";
SP.ListItemCollection listItemCollection = list.GetItems(camlQuery);
this.ctx.Load(listItemCollection);
this.ctx.ExecuteQuery();

SP.ListItem listItem = listItemCollection.FirstOrDefault(t => t.DisplayName == "NameOfTheListItem");
this.ctx.Load(listItem.FieldValuesAsText); 
this.ctx.ExecuteQuery();

//[Say, for one of the Id mentioned above.]
listItem.FieldValuesAsText["PostCategory"] = 2; 

listItem.Update(); 
this.ctx.ExecuteQuery(); 

To get the id of the listItem Ideas, you’ll have to re-connect to the SharePoint server and get the ID for the text Ideas from the List Category.

NOTE: Here, I have faced a strange issue. If I update any value of the Post Item before updating the lookupField value then the previous made changes were getting overwritten. So I have to ensure that the lookupField value should always get updated first before any other field.