Reading SharePoint Lists into an ADO.Net DataTable

[Feb 18, 2009: I’ve posted an update to show the newer technique suggested below by Kirk Evans, also compensating for some column naming issues.]

The other day, I needed to write some code that processed data from a SharePoint list. The list was hosted on a remote MOSS 2007 server.

Given more time, I’d have gone digging for an ADO.NET adapter, but I found some code that helped. Unfortunately, the code I found didn’t quite seem to work for my needs. Out of the box, the code missed several columns for no apparent reason.

Here’s my tweak to the solution:

(The ListWebService points to a web service like http://SiteHost/SiteParent/Site/_vti_bin/lists.asmx?WSDL )

private data.DataTable GetDataTableFromWSS(string listName)

{

ListWebService.Lists lists = new ListWebService.Lists();

lists.UseDefaultCredentials = true;

lists.Proxy = null;

//you have to pass the List Name here

XmlNode ListCollectionNode = lists.GetListCollection();

XmlElement List = (XmlElement)ListCollectionNode.SelectSingleNode(String.Format(“wss:List[@Title='{0}’]”, listName), NameSpaceMgr);

if (List == null)

{

throw new ArgumentException(String.Format(“The list ‘{0}’ could not be found in the site ‘{1}'”, listName, lists.Url));

}

string TechListName = List.GetAttribute(“Name”);

data.DataTable result = new data.DataTable(“list”);

XmlNode ListInfoNode = lists.GetList(TechListName);

System.Text.StringBuilder fieldRefs = new System.Text.StringBuilder();

System.Collections.Hashtable DisplayNames = new System.Collections.Hashtable();

foreach (XmlElement Field in ListInfoNode.SelectNodes(“wss:Fields/wss:Field”, NameSpaceMgr))

{

string FieldName = Field.GetAttribute(“Name”);

string FieldDisplayName = Field.GetAttribute(“DisplayName”);

if (result.Columns.Contains(FieldDisplayName))

{

FieldDisplayName = FieldDisplayName + ” (“ + FieldName + “)”;

}

result.Columns.Add(FieldDisplayName, TypeFromField(Field));

fieldRefs.AppendFormat(“”, FieldName);

DisplayNames.Add(FieldDisplayName, FieldName);

}

result.Columns.Add(“XmlElement”, typeof(XmlElement));

XmlElement fields = ListInfoNode.OwnerDocument.CreateElement(“ViewFields”);

fields.InnerXml = fieldRefs.ToString();

XmlNode ItemsNode = lists.GetListItems(TechListName, null, null, fields, “10000”, null, null);

// Lookup fields always start with the numeric ID, then ;# and then the string representation.

// We are normally only interested in the name, so we strip the ID.

System.Text.RegularExpressions.Regex CheckLookup = new System.Text.RegularExpressions.Regex(“^\\d+;#”);

foreach (XmlElement Item in ItemsNode.SelectNodes(“rs:data/z:row”, NameSpaceMgr))

{

data.DataRow newRow = result.NewRow();

foreach (data.DataColumn col in result.Columns)

{

if (Item.HasAttribute(“ows_” + (string)DisplayNames[col.ColumnName]))

{

string val = Item.GetAttribute(“ows_” + (string)DisplayNames[col.ColumnName]);

if (CheckLookup.IsMatch((string)val))

{

string valString = val as String;

val = valString.Substring(valString.IndexOf(“#”) + 1);

}

// Assigning a string to a field that expects numbers or

// datetime values will implicitly convert them

newRow[col] = val;

}

}

newRow[“XmlElement”] = Item;

result.Rows.Add(newRow);

}

return result;

}

// The following Function is used to Get Namespaces

private static XmlNamespaceManager _nsmgr;

private static XmlNamespaceManager NameSpaceMgr

{

get

{

if (_nsmgr == null)

{

_nsmgr = new XmlNamespaceManager(new NameTable());

_nsmgr.AddNamespace(“wss”, “http://schemas.microsoft.com/sharepoint/soap/”);

_nsmgr.AddNamespace(“s”, “uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882”);

_nsmgr.AddNamespace(“dt”, “uuid:C2F41010-65B3-11d1-A29F-00AA00C14882”);

_nsmgr.AddNamespace(“rs”, “urn:schemas-microsoft-com:rowset”);

_nsmgr.AddNamespace(“z”, “#RowsetSchema”);

}

return _nsmgr;

}

}

private Type TypeFromField(XmlElement field)

{

switch (field.GetAttribute(“Type”))

{

case “DateTime”:

return typeof(DateTime);

case “Integer”:

return typeof(int);

case “Number”:

return typeof(float);

default:

return typeof(string);

}

}