Updating list items in sharepoint
If the web service call successfully updates the item, your response code will be the string “No Conten”, otherwise you will have the error message.A Share Point site can include a variety of lists, such as contacts, calendars, announcements, and issues-tracking.
However, update an existing item in a Share Point lists has some tricks which we will show you in this post.
Also the header IF-MATCH has to be presented, but whenever you don’t have to worry about concurrency, the value (*) should be uses.
Otherwise you should obtain the etag value of a list item by performing a GET request before update the item. Create another dictionary called POST_Metadata where we will store the type of the item You should find the correct data type for the item you are trying to update. The data type name might change so don’t assume it is always your list name.
Regardless of the list type , the process is similar to add, edit, or delete list items.
Your list can include Text, Number, Choice, Currency, Date and Time, Lookup, Yes/No, and Calculated columns.