SharePoint Object Model Best Practices - Working with Lists and Folders

1.      Use SPList.GetItems instead of SPList.Items

Apply Filters, specify only fields needed to make the query more efficient. Apply pagination in increments of no more than 2000 items.

SPQuery query = new SPQuery();

SPListItemCollection spListItems ;

string lastItemIdOnPage = null; // Page position.

int itemCount = 2000

while (itemCount == 2000)

{

    // Include only the fields you will use.

    query.ViewFields = "<FieldRef Name=\"ID\"/><FieldRef Name=\"ContentTypeId\"/>";  

    query.RowLimit = 2000; // Only select the top 2000.

    // Include items in a subfolder (if necessary).

    query.ViewAttributes = "Scope=\"Recursive\"";

    StringBuilder sb = new StringBuilder();

    // To make the query order by ID and stop scanning the table, specify the OrderBy override attribute.

    sb.Append("<OrderBy Override=\"TRUE\"><FieldRef Name=\"ID\"/></OrderBy>");

    //.. Append more text as necessary ..

    query.Query = sb.ToString();

    // Get 2,000 more items.

    SPListItemCollectionPosition pos = new SPListItemCollectionPosition(lastItemIdOnPage);

    query.ListItemCollectionPosition = pos; //Page info.

    spListItems = spList.GetItems(query);

    lastItemIdOnPage = spListItems.ListItemCollectionPosition.PagingInfo;

    // Code to enumerate the spListItems.

    // If itemCount <2000, finish the enumeration.

    itemCount = spListItems.Count;

}

2.      Instead of using SPList.Items.GetItemById, use SPList.GetItemById(int id, string field1, params string[] fields). Specify the item identifier and the field that you want.

3.      Use SPList.ItemCount instead of SPList.Items.Count.

4.      Use SPList.GetItemByUniqueId(System.Guid) instead of SPList.Items[System.Guid]

5.      Use SPList.GetItemById(System.Int32) instead of SPList.Items[System.Int32]

6.      Use SPList.GetItemById(System.Int32) instead of SPList.Items.GetItemById(System.Int32)

7.      Use SPWeb.Lists[GUID] or SPWeb.GetList(strURL) is preferable to using SPWeb.Lists[strDisplayName].

·         Using the GUID is preferable because it is unique, permanent, and requires only a single database lookup.

·         The display name indexer retrieves the names of all the lists in the site and then does a string comparison with them.

8.      Use DeleteByID method instead of Delete()

SPSite site = new SPSite("site url");

SPWeb web = site.OpenWeb();

SPList list = web.Lists["custom list name"];

SPListItem item = list.GetItemById(1);

SPFile file = web.GetFile(item.Url);

SPFileVersionCollection collection = file.Versions;

ArrayList idList = new ArrayList();

foreach (SPFileVersion ver in collection)

{

  idList.Add(ver.ID);

}

foreach (int verID in idList)

{

try

{

  collection.DeleteByID(verID);

}

catch (Exception ex)

{

  MessageBox.Show(ex.Message); 

}

}