SharePoint Workflow:如何更新项目而不再触发工作流程

Question

我有一个SharePoint工作流程,只要项目发生变化就会运行.工作流与外部REST服务通信.如果服务返回一个字符串,我想用该字符串更新其中一个字段值.不幸的是,一旦当前工作流终止,此更新将触发此项的工作流的另一个实例.我最终得到了一个无限循环!

我怎么能防止这种情况发生？SPListItem具有Update(),UpdateOverwriteVersion()和SystemUpdate()方法,但它们似乎都不会阻止后续工作流被触发.

我可以检查项目的最后修改时间戳,并在最后一次更新发生在特定时间范围内时终止工作流程,但我正在寻找更强大的解决方案.

Answer 1

您可以使用一些扩展方法来静默更新项目.

public static class SPListItemExtensions
{
/// <summary>
/// Provides ability to update list item without firing event receiver.
/// </summary>
/// <param name="item"></param>
/// <param name="doNotFireEvents">Disables firing event receiver while updating item.</param>
public static void Update(this SPListItem item, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.Update();
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.Update();
    }
}

/// <summary>
/// Provides ability to update list item without firing event receiver.
/// </summary>
/// <param name="item"></param>
/// <param name="incrementListItemVersion"></param>
/// <param name="doNotFireEvents">Disables firing event receiver while updating item.</param>
public static void SystemUpdate(this SPListItem item, bool incrementListItemVersion, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.SystemUpdate(incrementListItemVersion);
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.SystemUpdate(incrementListItemVersion);
    }
}

/// <summary>
/// Provides ability to update list item without firing event receiver.
/// </summary>
/// <param name="item"></param>
/// <param name="doNotFireEvents">Disables firing event receiver while updating item.</param>
public static void SystemUpdate(this SPListItem item, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.SystemUpdate();
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.SystemUpdate();
    }
}

private class SPItemEventReceiverHandling : SPItemEventReceiver
{
    public SPItemEventReceiverHandling() { }

    new public void DisableEventFiring()
    {
        base.DisableEventFiring();
    }

    new public void EnableEventFiring()
    {
        base.EnableEventFiring();
    }


   }
}

Answer 2

更多链接,因为上述解决方案不适用于2010年:

• MSDN SPEventReceiverBase.EventFiringEnabled属性
• DisableEventFiring/EventFiringEnabled的工作原理

最好的解决方案:

• 禁用项目更新期间触发的Sharepoint项目事件