When creating a new list item, its fields can be set using syntax similar to string arrays. Note that these fields are not created on the fly and are defined by the schema of the list. These fields (or columns) must exist on the server otherwise the create will fail. All list items will have the Title field. Some lists may have required fields that must be filled out before the item will be published in the list.
In this example, the list is using the Announcements template. In addition to the title field, the list includes the Body field that will display the contents of the announcement on the list.
ClientContext clientContext = new ClientContext(siteUrl); List oList = clientContext.Web.Lists.GetByTitle("Announcements"); ListItemCreationInformation itemCreateInfo = new ListItemCreationInformation(); ListItem oListItem = oList.AddItem(itemCreateInfo); oListItem["Title"] = "My New Item!"; oListItem["Body"] = "Hello World!"; oListItem.Update(); clientContext.ExecuteQuery();