TryGetList Multiple List how to?

Question

 protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {

SPWeb web = SPContext.Current.Web;

        SPSiteDataQuery query = new SPSiteDataQuery();
        query.Lists = "<Lists MaxListLimit=\"3\">" +
  "<List ID=" + web.Lists.TryGetList("StaffNews").ID + " />" +
  "<List ID=" + web.Lists.TryGetList("CompanyNews").ID + " />" +
  "<List ID=" + web.Lists.TryGetList("ManagmentNews").ID + " />" +

"";

        string.Format("<OrderBy><FieldRef Name='Modified' Ascending='FALSE'></FieldRef></OrderBy>");
        query.Webs = "<Webs Scope=\"SiteCollection\" />";

        query.RowLimit = 10;


        DataTable dataTable = web.GetSiteData(query);

        Repeater1.DataSource = dataTable;

        Repeater1.DataBind();

Answer 1

You can retrieve information from several lists by SPSiteDataQuery. See this post for more details.

In this example the data is retrieved by this code.

using (SPSite site = new SPSite(ServerText.Text))
{
    using (SPWeb web = site.OpenWeb())
    {
        // Fetch using SPSiteDataQuery
        SPSiteDataQuery query = new SPSiteDataQuery();
        query.Lists = "<Lists ServerTemplate=\"105\" />";
        query.ViewFields = "<FieldRef Name=\"Title\" />" +  /* Title is LastName column */
                "<FieldRef Name=\"FirstName\" Nullable=\"TRUE\" Type=\"Text\"/>";
        query.Webs = "<Webs Scope=\"SiteCollection\" />";

        DataTable dataTable = web.GetSiteData(query);
        dataGridView3.DataSource = dataTable;
    }
}

The main line is

query.Lists = "<Lists ServerTemplate=\"105\" />";

How can you see this query is applied to the all lists that has "105" template id, this template is template for Contacts list, if you look at this line

web.Lists.Add("Contact List 2", "A contact list", SPListTemplateType.Contacts);

you see that Paul created the lists from Contacts template, thus values are retrieved from lists that are created before.

Try to google how to use query.Lists property in your case.

Answer 2

Building on Alexander's example, the <Lists> element actually supports a <List> element where you can specify the GUIDS of the lists you want to query.

using (SPSite site = new SPSite(ServerText.Text))
{
    using (SPWeb web = site.OpenWeb())
    {
        // Fetch using SPSiteDataQuery
        SPSiteDataQuery query = new SPSiteDataQuery();

        query.Lists = "<Lists MaxListLimit=\"3\">" +
              "<List ID="+web.Lists.TryGetList("StaffNews").ID+" />" +
              "<List ID="+web.Lists.TryGetList("CompanyNews").ID+" />" +
              "<List ID="+web.Lists.TryGetList("ManagmentNews").ID+" />" +
           "</Lists>";

        query.ViewFields = "<FieldRef Name=\"Title\" />" +  /* Title is LastName column */
                "<FieldRef Name=\"FirstName\" Nullable=\"TRUE\" Type=\"Text\"/>";
        query.Webs = "<Webs Scope=\"SiteCollection\" />";

        DataTable dataTable = web.GetSiteData(query);
        dataGridView3.DataSource = dataTable;
    }
}

More details here:

http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spsitedataquery.lists.aspx