"激活功能"步骤错误：对象引用未设置为对象的实例

Question

我创建了一个自定义定时器作业，并通过sharepoint中的一个特性事件来实现它。

当我试图激活它时，它显示了这个特殊的错误:

Object reference not set to an instance of an object.   at TimerJobExample.MyFeatureReceiver.FeatureActivated(SPFeatureReceiverProperties properties) in C:Documents and Settingsadmin-shuklag.INFRADEVMy DocumentsVisual Studio 2008ProjectsTimerJobExampleTimerJobExampleMyFeatureReceiver.cs:line 22 
   at Microsoft.SharePoint.SPFeature.DoActivationCallout(Boolean fActivate, Boolean fForce) 
   at Microsoft.SharePoint.SPFeature.Activate(SPSite siteParent, SPWeb webParent, SPFeaturePropertyCollection props, Boolean fForce) 
   at Microsoft.SharePoint.SPFeatureCollection.AddInternal(Guid featureId, SPFeaturePropertyCollection properties, Boolean force, Boolean fMarkOnly) 
   at Microsoft.SharePoint.SPFeatureCollection.Add(Guid featureId) 
   at Microsoft.SharePoint.WebControls.FeatureActivator.BtnActivateFeature_Click(Object objSender, EventArgs evtargs) 
   at System.Web.UI.WebControls.Button.OnClick(EventArgs e) 
   at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) 
   at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) 
   at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) 
   at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) 
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) 

错误行在

下面高亮显示

public override void FeatureActivated(SPFeatureReceiverProperties properties)
    {
        SPSite site = properties.Feature.Parent as SPSite;
        // make sure the job isn't already registered

//error line
      **foreach (SPJobDefinition job in site.WebApplication.JobDefinitions)**
        {
            if (job.Name == List_JOB_NAME)
                job.Delete();
        }

        SampleTimer listLoggerJob = new SampleTimer(List_JOB_NAME, site.WebApplication);
        SPMinuteSchedule schedule = new SPMinuteSchedule();
        schedule.BeginSecond = 0;
        schedule.EndSecond = 59;
        schedule.Interval = 5;
        listLoggerJob.Schedule = schedule;
        listLoggerJob.Update();
    }

有什么问题吗?

Answer 1

根据你的特征接收器，我只能看到两种可能性:

再次检查feature.xml中的Scope属性是否设置为Site。如果它被设置为Web，当你试图使用site变量时，你会得到一个Object Reference not set异常。
1. 正如Janis所说，查看MyCustomJob构造器内部。确保所有变量都被正确初始化。

Answer 2

问题在于功能的范围。它被设置为Web，并且要在此级别激活功能，您需要一个管理员帐户或具有更高权限的帐户。

您可以将应用程序池id添加到场管理帐户或