Unable to delete duplicate items from SharePoint List

Question

I am deleting duplicate items from a list. I have written the below code but somehow "if" condition is always true even field values are different hence deleting all the rows of the list except first row.

        ListItem duplicate = null;
        ClientContext context = new ClientContext("SITE URL");
        context.Credentials = new SharePointOnlineCredentials(struser, password);

        List announcementsList = context.Web.Lists.GetByTitle("LIST Name");

        var query = new CamlQuery();
        query.ViewXml =
           @"<View>
          <Query>
             <GroupBy>
               <FieldRef Name='Role' />
             </GroupBy>
         </Query>
        </View>";

        ListItemCollection oitems = announcementsList.GetItems(query);

        context.Load(oitems, items => items.Include(
             item => item["Contact"],
             item => item["Role"],
             item => item["Priority"]));

        context.ExecuteQuery();

            foreach(ListItem item in oitems.ToList())
            {
            if (duplicate != null)
            {                 
                if (item.FieldValues.ToString().Equals(duplicate.FieldValues.ToString()))
                {
                    item.DeleteObject();
                }
            }
                duplicate = item;
            }                
            context.ExecuteQuery();
        }

Answer 1

If your fields "Contact","Role","Prority" are text types then:

instead:

foreach(ListItem item in oitems.ToList())
{
    if (duplicate != null)
    {                 
         if (item.FieldValues.ToString().Equals(duplicate.FieldValues.ToString()))
         {
             item.DeleteObject();
         }
     }
     duplicate = item;
}

use:

foreach(ListItem item in oitems.ToList())
{
    if (duplicate != null)
    {                 
         if (item.FieldValues.Where(entry => 
                                    !Convert.ToString(item.FieldValues[entry.Key]).Equals(Convert.ToString(duplicate.FieldValues[entry.Key]))
                                    ).Count() > 0)
         {
             item.DeleteObject();
         }
         else
         {
             duplicate = item;
         }
     }
}