SharePoint2010企业开发最佳实践（八）---- SPWeb 对象

SPWeb.ParentWeb 属性

释放清理是由 SharePoint Foundation 和 SharePoint Server 自动处理的。

良好的编码实践

using (SPSite site = new SPSite("http://www.msiw.net/"))
{
    using (SPWeb web = site.OpenWeb())
    {
        SPList list = web.Lists["Announcements"];
        SPWeb parentWeb = list.ParentWeb; //No explicit dispose required.
    }
}

SPWeb.Webs 属性

SPWeb.Webs

SPWeb.Webs 属性将返回 SPWebCollection 对象。必须释放此集合中的 SPWeb 对象。

不良的编码实践

void WebsLeak()
{
    using (SPSite siteCollection = new SPSite("http://www.msiw.net/"))
    {
        using (SPWeb outerWeb = siteCollection.OpenWeb())
        {
            foreach (SPWeb innerWeb in outerWeb.Webs)
            {
                // SPWeb innerWeb leak.
            }
        } // SPWeb object outerWeb.Dispose() automatically called.
    } // SPSite object siteCollection.Dispose() automatically called.
}

良好的编码实践

void WebsNoLeak()
{
    using (SPSite siteCollection = new SPSite("http://www.msiw.net/"))
    {
        using (SPWeb outerWeb = siteCollection.OpenWeb())
        {
            foreach (SPWeb innerWeb in outerWeb.Webs)
            {
                try // Should be first statement after foreach.
                {
                    // ...
                }
                finally
                {
                    if(innerWeb != null)
                        innerWeb.Dispose();
                }
            }
        } // SPWeb object outerWeb.Dispose() automatically called.
    } // SPSite object siteCollection.Dispose() automatically called.
}

SPWeb.Webs.Add

SPWeb.Webs.Add 方法（或 SPWebCollection.Add）会创建并返回新的 SPWeb 对象。应该释放从此方法调用中返回的任何 SPWeb 对象。

不良的编码实践

void WebsAddLeak(string strWebUrl)
{
    using (SPSite siteCollection = new SPSite("http://www.msiw.net/"))
    {
        using (SPWeb web = siteCollection.OpenWeb())
        {
            SPWeb addedWeb = web.Webs.Add(strWebUrl);   // Will leak.

} // SPWeb object web.Dispose() automatically called.
} // SPSite object siteCollection.Dispose() automatically called.
}

良好的编码实践

void WebsAddNoLeak(string strWebUrl)
{
    using (SPSite siteCollection = new SPSite("http://www.msiw.net/"))
    {
        using (SPWeb web = siteCollection.OpenWeb())
        {
            using (SPWeb addedWeb = web.Webs.Add(strWebUrl))
            {
                //..
            }

} // SPWeb object web.Dispose() automatically called.
} // SPSite object siteCollection.Dispose() automatically called.
}

SPWeb.Webs[] 索引运算符

SPWeb.Webs[] 索引运算符会针对每次访问返回一个新的 SPWeb 对象。将会通过调用 OpenWeb 方法来创建 SPWeb，即使已经访问了该对象也不例外。以下代码示例会导致在 .NET Framework 使用的内存中长期保留这些对象。

不良的编码实践 #1

使用 For 循环

int i;

SPWeb oSPWeb, oSPWeb2;
SPSite oSPSite = SPControl.GetContextSite(Context);

oSPWeb = oSPSite.OpenWeb();

for(i = 0;i < oSPWeb.Webs.Count;i++)
{
oSPWeb2 = oSPWeb.Webs[i];
BuildTableRow(oDisplayTable, "Web", oSPWeb2.Title);
}

不良的编码实践 #2

使用 foreach 循环

SPWeb oSPWeb, oSPWeb2;
SPSite oSPSite = SPControl.GetContextSite(Context);

oSPWeb = oSPSite.OpenWeb();

foreach(SPWeb oSPWeb2 in oSPWebe.Webs)
{
BuildTableRow(oDisplayTable, "Web", oSPWeb2.Title);
}

建议的修复方法是在每次循环结束后进行释放。

良好的编码实践 #1

使用 For 循环

int i;

SPWeb oSPWeb, oSPWeb2;
SPSite oSPSite = SPControl.GetContextSite(Context);

oSPWeb = oSPSite.OpenWeb();

for(i = 0;i < oSPWeb.Webs.Count;i++)
{
   oSPWeb2 = oSPWeb.Webs[i];
   BuildTableRow(oDisplayTable, "Web", oSPWeb2.Title);
   oSPWeb2.Dispose();
}

oSPWeb.Dispose();

良好的编码实践 #2

使用 foreach 循环

SPWeb oSPWeb, oSPWeb2;
SPSite oSPSite = SPControl.GetContextSite(Context);

oSPWeb = oSPSite.OpenWeb();

foreach(SPWeb oSPWeb2 in oSPWeb.Webs)
{
BuildTableRow(oDisplayTable, "Web", oSPWeb2.Title);
oSPWeb2.Dispose();
}

oSPWeb.Dispose();

良好的编码实践 #3

将 for 循环与自动释放结合使用

int i;

SPWeb oSPWeb, oSPWeb2;
SPSite oSPSite = SPControl.GetContextSite(Context);

using(oSPWeb = oSPSite.OpenWeb())
{
   for(i = 0;i < oSPWeb.Webs.Count;i++)
   {
      Using(oSPWeb2 = oSPWeb.Webs[i])
      {
         BuildTableRow(oDisplayTable, "Web", oSPWeb2.Title);
      }
   }
}

转载于:https://www.cnblogs.com/shangmeizhai/archive/2011/02/11/1951570.html