从Sharepoint的List中获取不重复的item

枫叶飞翔

　　比如有这么一个表格叫做Movies



Movie          Year
-----          ----
Fight Club     1999
The Matrix     1999
Pulp Fiction   1994
　　用CAML删选出去年重复的年份，剩下1999,1994绑定到Dropdown Control
　　由于CAML不能去除重复，只能全部删选出来后，利用DataView实现



            SPList movies = SPContext.Current.Web.Lists["Movies"];
SPQuery query = new SPQuery();
query.Query = "<OrderBy><FieldRef Name='Year' /></OrderBy>";
DataTable tempTbl = movies.GetItems(query).GetDataTable();
DataView v = new DataView(tempTbl);
String[] columns = {"Year"};
DataTable tbl = v.ToTable(true, columns);
　　DataTable tbl就是只剩下1999,1994了。
　　还有两个方法能够实现，但是效率不知道哪个好，当数据量一大可能就很会影响性能。
　　使用客户端对象模型一个对比



foreach (SPListItem listItem in listItems)
{
if ( null == ddlYear.Items.FindByText(listItem["Year"].ToString()) )
{
ListItem ThisItem = new ListItem();
ThisItem.Text = listItem["Year"].ToString();
ThisItem.Value = listItem["Year"].ToString();
ddlYear.Items.Add(ThisItem);
}
}
　　使用Linq



// Retrieve the list. NEVER use the Web.Lists["Movies"] option as in the other examples as this will enumerate every list in your SPWeb and may cause serious performance issues
var list = SPContext.Current.Web.Lists.TryGetList("Movies");
// Make sure the list was successfully retrieved
if(list == null) return;
// Retrieve all items in the list
var items = list.GetItems();
// Filter the items in the results to only retain distinct items in an 2D array
var distinctItems = (from SPListItem item in items select item["Year"]).Distinct().ToArray()
// Bind results to the repeater
Repeater.DataSource = distinctItems;
Repeater.DataBind();