LINQ 删除多行 在线等 急

[Thirteen07]

我想从Activities这个表中删除所有zhanghao == "zb07nju"的行，但是总是弹出"Sequence contains more than one element "，请问怎么办？

DataClassesDataContext DC = new DataClassesDataContext();
        var query = from a in DC.Activities
                    where a.ZhangHao == "zb07nju"
                    select a;
        DC.Activities.DeleteAllOnSubmit(query);
        DC.SubmitChanges();

[Thirteen07]

DataClassesDataContext DC = new DataClassesDataContext();
        var query = (from a in DC.Activities
                    where a.ZhangHao == "zb08nju"
                 select new {a.ZhangHao,a.Description,a.DateTime}).SingleOrDefault();
        DC.Activities.DeleteAllOnSubmit(query);
        DC.SubmitChanges();

错误信息为“The type arguments for method 'System.Data.Linq.Table<Activity>.DeleteAllOnSubmit<TSubEntity>(System.Collections.Generic.IEnumerable<TSubEntity>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.”

[Xuon]

DataClassesDataContext DC = new DataClassesDataContext();
        var query = from a in DC.Activities
                    where a.ZhangHao == "zb09nju"
                    select a;

        foreach(var item in query)
        {
            DC.Activities.DeleteAllOnSubmit(item);
        }

        if(query.Count()>0)
        {
            DC.SubmitChanges();
        }

这样试试

[Xuon]

也可以这样写foreach
foreach(Activities item in query)

思路是先获得单个实体对象，再删除。
这就是楼上的告诉你用SingleOrDefault();的原因。

[Thirteen07]

4楼的方法我早就试过了，还是不行的，我今天知道怎么做了，不过还是谢谢了

[Thirteen07]

4楼的方法我早就试过了，还是不行的，我今天知道怎么做了，不过还是谢谢了

[Thirteen07]

又试过了另一种方法，还是不行，出类型转换错误“The type 'AnonymousType#1' cannot be used as type parameter 'TSubEntity' in the generic type or method 'System.Data.Linq.Table<TEntity>.DeleteAllOnSubmit<TSubEntity>(System.Collections.Generic.IEnumerable<TSubEntity>)'. There is no implicit reference conversion from 'AnonymousType#1' to 'Activity'.”，


求救

 DataClassesDataContext DC = new DataClassesDataContext();
        var query = from a in DC.Activities
                    where a.ZhangHao == "zb09nju"
                    select new { a.ZhangHao,a.DateTime,a.Description};
        DC.Activities.DeleteAllOnSubmit(query);
        DC.SubmitChanges();

[PandaIT]

 var query =(from a in DC.Activities
                    where a.ZhangHao == "zb09nju"
                    select new { a.ZhangHao,a.DateTime,a.Description}).SingleOrDefault();

[Xuon]

翻了一下我以前写的，这样应该没问题了。

        DataClassesDataContext DC = new DataClassesDataContext();
        var query = from a in DC.Activities
                    where a.ZhangHao == "zb09nju"
                    select a;

        if(query.Count()>0)
        {
            Activities[] actiObjsArr=new Activities[query.Count()];
            int i=0;
            foreach(Activities item in query)
            {
                actiObjsArr[i]=item;
                ++i;
            }

            for (int n= 0; n < i; ++n)
            {
		DC.Activities.Remove(actiObjsArr[n]);
                DC.SubmitChanges();
	    }
        }