为什么dataContext.GetChangeSet（）。Deletes.Count（）总是返回0？ [英] Why is dataContext.GetChangeSet().Deletes.Count() always returning 0?

问题描述

我有这回事：

var customerIdsToDelete = new {1, 2, 3};
var dataContext = new DataContext();
var customersToDelete = (from c in data.Customers
                         where  customerIdsToDelete.Contains(c.CustomerID)
                         select c);
data.Customers.DeleteAllOnSubmit(customersToDelete);
data.SubmitChanges();

var deletedCount = data.GetChangeSet().Deletes.Count();

即使当客户成功删除 deletedCount 将是0。

为什么呢？而这将是计数客户数的正确的方式删除？

Why? And what would be the "correct" way of counting the number of customers deleted?

推荐答案

由于您已提交的变化。一旦调用的SubmitChanges 已经取得了那么有没有删除，因此（正确地）返回计数为零。要获取删除（或者被删除）的项目数那就试试这个（即确定计数推动改变之前）：

Because you've submitted the changes already. Once the call to SubmitChanges has been made then there are no deletes, and therefore (correctly) a count of zero is returned. To get the number of items deleted (or, to be deleted) then try this (i.e. determining the count prior to pushing the changes):

...

var deletedCount = data.GetChangeSet().Deletes.Count();
data.SubmitChanges();

...

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