Nick Grattan’s SharePoint Blog

Many functions that the SharePoint web interface does you can do through calling web services provided by SharePoint – this is thanks to the SOA application architecture. Here’s a starting guide to get you going. This example uses a WinForm application but the same techniques can be used with ASP.NET applications. This program gets the names and GUIDs of all lists in the site (but not sub-sites) and displays the names in a list box. When the user selects a list name the GUID for the list will be displayed:

First, you need to create a web reference to the SharePoint web service. The URL for the web reference looks like:

http://server:port/sites/intranet/projectx/_vti_bin/lists.asmx

The URL includes the server and port, and the path to the site which you want to program against – “projectx” in this case.

Now the coding starts. First, create an instance of the web service (the proxy name is “moss2007″ in this case) for the “Lists” SharePoint web service. Then set the credentials used to authenticate against the service. In the WinForm example this is the currently logged on user:

    moss2007.Lists lst = new moss2007.Lists();
  lst.Credentials = System.Net.CredentialCache.DefaultCredentials;

Now a call can be made to get the “List” – this is returned as an XmlNode list:

    XmlNode nl = lst.GetListCollection();

In this example, the list is added to a list box. Each List in SharePoint has an “ID” which is a GUID, and when using lists through web services you should use the “ID” to refer to a list and not its name. Therefore, the list of names is going to be added to a list box and the GUIDs stored against them. Then, when the user selects a list the list can be accessed through the GUID. To do this, a class is created to manage items in the list box:

public class LstDataItem
{
     public LstDataItem(string sDisplay, Guid gGuid)
     {
         display = sDisplay;
         theGuid = gGuid;
     }

     private String display;

     public String Display
     {
         get { return display; }
         set { display = value; }
     }

     private Guid theGuid;

     public Guid TheGuid
     {
         get { return theGuid; }
         set { theGuid = value; }
     }
 
     public override string ToString()
     {
         return Display;
     }
}

The list can now be loaded into the list box:

foreach (XmlNode nd in nl.ChildNodes)
{
    lstLists.Items.Add(new LstDataItem(nd.Attributes["Title"].Value, 
        new Guid(nd.Attributes["ID"].Value)));
}

This code iterates over the list of nodes, and extracts the name from the “Title” attribute and the GUID from the “ID” attribute. These are added to the list box Items collection. Finally, an event handler is created to respond to the user selecting an item from the list box:

private void lstLists_SelectedIndexChanged(object sender, EventArgs e)
{
    LstDataItem ldi = (LstDataItem)lstLists.SelectedItem;
    if (ldi != null)
    {
        MessageBox.Show(ldi.TheGuid.ToString());
    }
}
 

Here is the complete code for loading the list in the Form’s Load event. It includes exception handling for errors thrown by the SharePoint web service:

private void Form1_Load(object sender, EventArgs e)
{
    try
    {
        moss2007.Lists lst = new moss2007.Lists();
        lst.Credentials = System.Net.CredentialCache.DefaultCredentials;

        XmlNode nl = lst.GetListCollection();

        foreach (XmlNode nd in nl.ChildNodes)
        {
            lstLists.Items.Add(new LstDataItem(nd.Attributes["Title"].Value,
               new Guid(nd.Attributes["ID"].Value)));
        }
    }
    catch (System.Net.WebException wex)
    {
        MessageBox.Show(wex.Message);
    }
    catch (System.Web.Services.Protocols.SoapException ex)
    {
        MessageBox.Show(“Message:\n” + ex.Message + “\nDetail:\n” +
            ex.Detail.InnerText + “\nStackTrace:\n” + ex.StackTrace);
    }
}