如何确定ObservableCollection< T>中的行是否实际上改变了

本文介绍了如何确定ObservableCollection< T>中的行是否实际上改变了的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个ObservableCollection

I have an ObservableCollection

私有静态CertOrigin_Entities db = new CertOrigin_Entities(); 私有静态ObservableCollection ocSHIPPING_DTL;

private static CertOrigin_Entities db = new CertOrigin_Entities(); private static ObservableCollection ocSHIPPING_DTL;

我有一个WPF Datagrid，我在以后进行绑定

I have a WPF Datagrid that I do late binding on

private void btn_SEARCH_Click(object sender, RoutedEventArgs e) { string sCI = this.txt_SEARCH.Text; var sd = (db.TBL_SHIPPING.Where(x => x.CommercialInvoiceNumber == sCI)).ToList(); if (sd.Count() > 0) { iID = (int)sd[0].SHIPPING_ID; var query = (db.v_wpf_cert_origin.Where(x => x.SHIPPING_ID == iID)); ocSHIPPING_DTL = new ObservableCollection<v_wpf_cert_origin>(query.ToList()); dgCOO.ItemsSource = ocSHIPPING_DTL; var cust = (from x in db.TBL_CUSTOMER join y in db.TBL_REQUISITION on x.CUSTOMER_ID equals y.CUSTOMER_ID join z in db.TBL_SHIPPING on y.REQ_ID equals z.REQ_ID where z.SHIPPING_ID == iID select new {CUST = x.CustomerName}).ToList(); this.lbl_CUSTOMER.Content = cust[0].CUST.ToString(); } }

我正在更新SQL Server数据库 在按钮后面并在窗口上关闭

I am updating the SQL server database behind a button and on the window close

private static bool _SaveChanges() { DbTransaction _dbTransaction = null; db.Connection.Open(); using (_dbTransaction = db.Connection.BeginTransaction()) { try { db.SaveChanges(); db.AcceptAllChanges(); _dbTransaction.Commit(); db.Connection.Close(); } catch (TransactionAbortedException ex) { db.Connection.Close(); throw ex; } return true; } }

这就是我正在发生的事情... 在我的数据网格中，我有一个文本框

Here is what is happening to me... In my datagrid, I have a textbox

<DataGridTemplateColumn Header="Hs Tarriff Class #:" Width="125" IsReadOnly="False"> <DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBox Text="{Binding Path=HsTarriffClassNumber, UpdateSourceTrigger=PropertyChanged, NotifyOnTargetUpdated=True}" Name="txt_HsTarriffClassNumber" /> </DataTemplate> </DataGridTemplateColumn.CellTemplate>

如果文本框的值为5864.193.45，而我将其更改为5864.193.46，然后又返回5864.193.45，则ObservableCollection将记录保存为更改的记录，但是我不希望它将记录另存为它没有改变.

If the text box has 5864.193.45 as the value and I change it to 5864.193.46 then back to 5864.193.45 the ObservableCollection saves the record as the record did change, however I do not want it to save the record as it did not change.

更改的主要问题是这个. 我桌上有3个触发器

The primary issue of the change is this. I have 3 triggers on the table

1-更新之后，审计触发器将删除的触发器插入到另一个数据库中

1 - After update Audit trigger that takes the deleted and inserts it into another database

2-在更新审核触发器之后，该触发器向许多人发送电子邮件，指出用户更改了数据，因此他们需要重新打印文书工作并将其发送给海关.

2 - After Update Audit trigger that sends an email to a multidude of people stating that the user changed the data and they need to reprint the paperwork and send it to customs

3-在更新"触发器上，该触发器将更新不同的表，并将last_used_tarrif字段设置为等于用户更改的值.

3 - On Update trigger that updates a different table and sets the last_used_tarrif field equal to the value the user changed.

如果用户未实际更改数据，则以上任何一项均不触发. 有没有办法检查记录是否实际更改?

If the user did not actually change the data none of the above should fire. Is there a way to check if the record actually changed?

我可以将可观察集合中的记录与表中的记录进行比较，而仅更新实际上不同的记录吗?

Can I compare the records in the observable collection to the records in the table and only update those that are actually different?

有什么建议吗?

推荐答案

因为您已将UpdateSourceTrigger设置为PropertyChanged(请参阅 MSDN:Binding.UpdateSourceTrigger ，每次检测到更改时，都会采取措施.

Because you have the UpdateSourceTrigger set to PropertyChanged (see MSDN: Binding.UpdateSourceTrigger, every time it detects a change, it will action a change.

从5864.193.45更改为5864.193.46是一项操作，然后从5864.193.46更改为5864.193.45是另一项操作.

Changing from 5864.193.45 to 5864.193.46 is one action, then 5864.193.46 to 5864.193.45 is another action.

过程1: 您还可以将UpdateSourceTrigger更改为LostFocus(UpdateSourceTrigger=LostFocus)，这样就可以使更改在单击其他位置之前不起作用.这样，当您从5864.193.45更改为5864.193.46，然后从5864.193.46更改为5864.193.45时，直到离开该文本区域，该更改才会生效.

Process 1: You could also change UpdateSourceTrigger to LostFocus (UpdateSourceTrigger=LostFocus), this makes it so that the change doesn't get actioned until you click somewhere else. This way when you change from 5864.193.45 to 5864.193.46 , then 5864.193.46 to 5864.193.45 it wouldn't action the change until you leave that text area.

过程2: 您总是可以实现一个主要的ObservationCollection，然后仅在调用_SaveChanges()时进行比较.

Process 2: You could always implement a master ObservationCollection and then only compare when you call _SaveChanges().