信息系统开发平台OpenExpressApp － 支持差异保存

CSLA目前通用做法是整个对象在网络上传输，客户端更新时不管是更新了多少内容，它会把整个对象返回到服务器端。如果这个对象有成百上千条记录，而只更新了一两条记录，那么回传整个对象无疑是一个很大的浪费。在业务逻辑不需要整个对象的情况下，我们可以做差异更新，只回传增加、更新或删除的数据到服务器端。

[Command(CommandNames.Save_Bill, Label = "保存", ToolbarType = ToolbarType.Main, ModuleType = ModuleType.Bill, ToolTip = "保存记录")]
public class SaveBillCommand : WPFViewCommand
{
public override void Execute(ObjectView view)
{
DiffSaveCommand.Execute(view.CurrentObject as BusinessBase);
}
}

[Serializable]
public class DiffSaveCommand: CommandBase
{
public static void Execute(BusinessBase businessBase)
{
DiffSaveCommand cmd = new DiffSaveCommand(businessBase);
cmd = DataPortal.Execute<DiffSaveCommand>(cmd);

MakeOldRecurChildObject(businessBase); //记住：调用成功后，把原始对象状态设置为Old
}

//设置原始对象状态
private static void MakeOldRecurChildObject(BusinessBase businessBase)
{
businessBase.MarkOld();
BusinessObjectInfo boInfo = ApplicationModel.GetBusinessObjectInfo(businessBase.GetType());

foreach (var item in boInfo.BOsPropertyInfos)
{
//如果是懒加载属性，并且没有加载数据时，不需要遍历此属性值
if (!businessBase.FieldExists(item.Name)) continue;
IList childs = businessBase.GetPropertyValue(item.Name) as IList;
((childs as IEditableCollection).GetDeletedList() as IList).Clear();
for (int i = childs.Count - 1; i >= 0; i--)
{
BusinessBase child = childs[i] as BusinessBase;
if (child.IsDirty) MakeOldRecurChildObject(child);
}
}
}

private BusinessBase diffBo;
private DiffSaveCommand(BusinessBase businessBase)
{
diffBo = (businessBase as ICloneable).Clone() as BusinessBase;
//抱着传送对象只包含更新过的对象
DeleteNotDirtyData(diffBo);
}

protected override void DataPortal_Execute()
{
(diffBo as ISavable).Save();
}

//删除没有更改的子对象
private void DeleteNotDirtyData(BusinessBase businessBase)
{
BusinessObjectInfo boInfo = ApplicationModel.GetBusinessObjectInfo(businessBase.GetType());

//删除没有变化的子对象
foreach (var item in boInfo.BOsPropertyInfos)
{
//如果是懒加载属性，并且没有加载数据时，不需要遍历此属性值
if (!businessBase.FieldExists(item.Name)) continue;
IList childs = businessBase.GetPropertyValue(item.Name) as IList;
for (int i = childs.Count - 1; i >= 0; i--)
{
BusinessBase child = childs[i] as BusinessBase;
if (!child.IsDirty)
{
(childs as IEditableCollection).RemoveChild(child);
((childs as IEditableCollection).GetDeletedList() as IList).Remove(child);
}
else
DeleteNotDirtyData(child as BusinessBase);
}

}
}
}

/// 是否存在属性值，懒加载还没加载时不存在
public bool FieldExists(string propertyName)
{
PropertyInfoList list = PropertyInfoManager.GetRegisteredProperties(this.GetType());
foreach(var item in list)
{
if (item.Name == propertyName)
return FieldManager.FieldExists(item);
}
return false;
}

public static void Execute(BusinessBase businessBase)
{
DiffSaveCommand cmd = new DiffSaveCommand(businessBase);
cmd = DataPortal.Execute<DiffSaveCommand>(cmd);

MakeOldRecurChildObject(businessBase); //记住：调用成功后，把原始对象状态设置为Old
}