步步为营 SharePoint 开发学习笔记系列 十一、SharePoint 对list操作

西大

　　概要
　　在sharepoint中的自定义web part会涉及到对list里面的item进行操作，这篇文单将会讲解如何修改list里的item。
　　我们先看一个示例

        /// <summary>
///
/// </summary>
/// <param name="ID"></param>
/// <returns></returns>
public SPListItemCollection GetSPListItemCollection(string ID)
{
SPListItemCollection itemCollection = new SPListItemCollection();
SPSecurity.RunWithElevatedPrivileges(
delegate
{
using (SPSite spsite = new SPSite(this.CurrentUrl))
{
using (SPWeb spWeb = spsite.OpenWeb())
{
SPList listInstance = spWeb.Lists[this.ListName];
SPQuery query = new SPQuery();
query.Query = "<Where><Eq><FieldRef Name='ID' /><Value Type='Counter'>" + ID + "</Value></Eq></Where>";
itemCollection = listInstance.GetItems(query);
}
}
}
);
return itemCollection;
}
　　SPSecurity.RunWithElevatedPrivileges()是用来提高操作权限级别来操作站点!
　　用法:
　　SPSecurity.RunWithElevatedPrivileges(delegate() {代码});提高权限将是让代码以sharepoint\system所具有的权限来执行!
　　更改指定的item代码

        public string AddNewItem()
{
string retVal = string.Empty;
try
{
SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite site = new SPSite(SPContext.Current.Web.Url))
{
using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists["TEST"];
SPListItem item = list.Items.Add();
item["Title"] = string.Format("Test at {0}", DateTime.Now.ToString());
item.Update();
}
}
retVal = "operation  success!";
});
}
catch (Exception ex)
{
retVal += ex.Message;
}
return retVal;
}

　　如果修改的不留痕迹，要使用SystemUpdate;
　　示例如下:

        public string AddNewItem()
{
string retVal = string.Empty;
try
{
SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite site = new SPSite(SPContext.Current.Web.Url))
{
using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists["TEST"];
SPListItem item = list.Items.Add();
item["Title"] = string.Format("Test at {0}", DateTime.Now.ToString());
item.SystemUpdate();
}
}
retVal = "operation  success!";
});
}
catch (Exception ex)
{
retVal += ex.Message;
}
return retVal;
}

　　在很多时候我们需要设置允许不安全的修改。使用这个AllowUnsafeUpdates.
　　示例如下:

        public string AddNewItem()
{
string retVal = string.Empty;
try
{
SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite site = new SPSite(SPContext.Current.Web.Url))
{
using (SPWeb web = site.OpenWeb())
{
web.AllowUnsafeUpdates = true;
SPList list = web.Lists["TEST"];
SPListItem item = list.Items.Add();
item["Title"] = string.Format("Test at {0}", DateTime.Now.ToString());
item.SystemUpdate();
web.AllowUnsafeUpdates = false;
}
}
retVal = "operation  success!";
});
}
catch (Exception ex)
{
retVal += ex.Message;
}
return retVal;
}

　　在sharepoint里面删除一条item的话可以进行如下操作.

        /// <summary>
///
/// </summary>
/// <returns></returns>
private SPList GetCurrentList()
{
using (SPSite siteCollection = new SPSite(SPContext.Current.Web.Url))
{
using (SPWeb web = siteCollection.OpenWeb())
{
SPList list = web.Lists[this.ListName];
return list;
}
}
}
/// <summary>
///
/// </summary>
/// <param name="id"></param>
/// <param name="version"></param>
/// <param name="recycle"></param>
public void DeleteItemByIDVersion(int id, int version, bool recycle)
{
SPListItem item = GetCurrentList().GetItemById(id);
if (recycle)
{
item.Versions.GetVersionFromID(version).Recycle();
}
else
{
item.Versions.GetVersionFromID(version).Delete();
}
}

/// <summary>
/// Property that holds the list name.
/// </summary>
public override string ListName
{
get { return "Test"; }
}

　　如果只取item的发布过的版本的数据，可以做如下处理.

        private NewEntity GetLastApproveVersionByItem(SPListItem item)
{
NewEntity result = null;
if (item == null) return result;
if (item.Level == SPFileLevel.Published)
{
result = this.ConvertToEntity(item);
}
else if (item.Versions != null && item.Versions.Count > 0)
{
foreach (SPListItemVersion itemVersion in item.Versions)
{
if (itemVersion.Level == SPFileLevel.Published)
{
result = this.ConvertToEntity(itemVersion);
break;
}
}
}
return result;
}

　　总结
　　sharepoint 对list的操作，主要有增加、删除和修改list里面的item数据，要注意的是这里打开的是当前操作的site。SPContext.Current.Web.Url取的是当前打开页面的值.
　　作者：spring yang
　　出处：http://www.cnblogs.com/springyangwc/
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