如何找到缺少的ID号Gridview控件？ [英] How to find missing ID Number Gridview control?

问题描述

我有一个网格视图，如..

I have a grid view like..

sno     Name   ID

 1      AAA     1
 2      BBB     2
 3      CCC     3
 4      DDD     6

如果您观察到以上Gridview ..在此gridview中缺失4和5 ID号码..现在我想显示一条4,5 ID遗漏的提醒信息...



我该怎么办？



请帮助我

If you observe above Gridview..In this gridview missing 4 and 5 ID numbers..Now i want to shows an alert message like 4,5 ID are missing...

How can i do this?

Please help me

推荐答案

1. 循环通过行。
2. 在列表中存储 ID 。
3. 循环通过列表并比较当前和下一个 Id 。如果差异大于1，则找到缺少的 Id 并存储在另一个列表中。
4. 最后显示那些 ID 。

1. Loop through the Rows.
2. Store Ids in a List.
3. Loop through the List and compare current and next Id. If difference is greater than 1, then find missing Id and store in another List.
4. At last show the those Ids.

1。获取第一行ID和最后一行ID。

2.创建可枚举范围

1. Fetch the First row id and last row id.
2. create Enumerable range

IEnumerable<int> nos= Enumerable.Range(firstrowid, lastrowid);

3.使用linq来丢失nos。

3. use linq to get missing nos.

var missingid = from a in nos
              where !(from b in gvRows.AsEnumerable()
                        select b["id"])
                        .Contains(a)
              select a;

这个问题经常出现，遗憾的是，最常见（也是最便携）的答案是创建一个临时表保留应该存在的ID，并进行左连接。 MySQL和SQL Server之间的语法非常相似。唯一真正的区别是临时表语法。

This question often comes up, and sadly, the most common (and most portable) answer is to create a temporary table to hold the IDs that should be there, and do a left join. The syntax is pretty similar between MySQL and SQL Server. The only real difference is the temporary tables syntax.

declare @id int
declare @maxid int

set @id = 1
select @maxid = max(id) from tbl

create table #IDSeq
(
    id int
)

while @id < @maxid --whatever you max is
begin
    insert into #IDSeq values(@id)

    set @id = @id + 1
end

select
    s.id
from
    #idseq s
    left join tbl t on
        s.id = t.id
 where t.id is null

 drop table #IDSeq

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