如何使用LINQ在foreach命令中插入多行? [英] How to Insert Multiple Rows in a foreach command with LINQ?

问题描述

我写了以下几行:

foreach (var catId in CatIds)
{
    AdCategory.AdId = LastAd.AdID;
    AdCategory.CategoryId = catId;
    EngineDB.Ad_Categories.InsertOnSubmit(AdCategory);
    EngineDB.SubmitChanges();
}

CatIds是一个整数数组.
此命令正确插入第一个元素，但下一个循环会导致此异常:
无法添加已经存在的实体."
我该如何解决.
请尽快帮助我！

and CatIds is an Integer Array.
this command inserts first element correctly but next loop causes this exception:
"Cannot add an entity that already exists."
How can I fix it.
please help me as soon as posible!

推荐答案

您需要在循环中创建一个新的AdCategory.否则，由于错误状态，您打算一次又一次地插入同一对象.

You need to create a new AdCategory in the loop. Otherwise, as the error states, you are tyring to insert the same object again and again.

您还应该移动

EngineDB.SubmitChanges();

在循环之外，因此您只需对数据库进行1次调用.

outside of the loop so you only make 1 call to the database.

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