从Sharepoint的List中获取不重复的item

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();