使用LINQ删除表中的行到SQL [英] Deleting rows in a table with Linq to SQL

问题描述

我有哪些有场ID，groupId和MEMBERID表groupmembers体育数据库。我从一个来自所谓的CheckBoxList和txtRemoveGroupMember的GROUPID文本框中MEMBERID。现在我想删除至极既有GROUPID和MEMBERID行。
我已经试过这段代码：

I have a sports database with a table groupmembers which have the fields ID, groupID and memberID. I get the memberID from a textbox called txtRemoveGroupMember and the groupID from a checkboxlist. Now i want to delete the rows wich has both the groupID and the memberID. I have tried this code:

foreach(ListItem listItem in cblRemoveMemberFromGroup.Items)
{
       int memberid = Convert.ToInt32(txtRemoveGroupMember.Text);
       int groupid = Convert.ToInt32(listItem.Value);

       var removeFromGroup = from gm in dataContext.GroupMembers
            where (gm.memberID == memberid) && (gm.groupID == groupid)
            select gm;

       dataContext.GroupMembers.DeleteOnSubmit(removeFromGroup);
       dataContext.SubmitChanges();
}

但是我得到这个错误：错误7参数1：不能从转换'系统.Linq.IQueryable'到'GSI_side.GroupMember

But i get this error: Error 7 Argument 1: cannot convert from 'System.Linq.IQueryable' to 'GSI_side.GroupMember'

和这个错误：错误6的最好重载方法匹配'System.Data.Linq.Table.DeleteOnSubmit（GSI_side .GroupMember）'有一些无效参数

And this error: Error 6 The best overloaded method match for 'System.Data.Linq.Table.DeleteOnSubmit(GSI_side.GroupMember)' has some invalid arguments

希望有人能帮助我想出解决办法！

Hope someone can help me figure this out!

推荐答案

您必须调用.ToList（）

You have to call .ToList()

var items = removeFromGroup.ToList();
foreach (var item in items)
  dataContext.GroupMembers.DeleteOnSubmit(item);

有关批量删除我使用的这个，因为LINQ to SQL的首次加载它是要删除的整个数据，那么它的每个删除每个

For batch deletes I use this, because LINQ to SQL first loads the entire data which is going to be deleted, then it does the deletes each by each.

的 https://terryaney.wordpress.com/2008/04/14/batch-updates-and-deletes-with-linq-to-sql/

的 https://github.com/longday/LINQ-to-SQL-Batch-Updates-Deletes

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