创建数据集时出错 [英] Error creating a dataset

问题描述

我正在尝试创建一个包含6个表和5个关系的数据集。我在Form_Load事件中创建它。但是我一直收到以下错误...


system.data.dll中发生了'System.ArgumentNullException'类型的未处理异常

其他信息：''column''参数不能为null。

代码在此行停止...

Dim rel_Booking_CaraBook As New DataRelation（" dsFullBooking" ;，dsFullBooking.Tables（" dtBooking"）。列（" Booking ID"），dsFullBooking.Tables（" dtCaraBooking"）。列（" Boo kingID"））


有谁知道我做错了什么？

这是我的完整代码....


Dim dsFullBooking As New DataSet（）

''创建客户数据表

da = New SqlDataAdapter（" SELECT * FROM Client"，Cn）

da.Fill（dsFullBooking，" dtClient"）

''创建预订数据表

da =新SqlDataAdapter（" SELECT * FROM Booking"，Cn）

da。填写（dsFul lBooking，dtBooking）

''创建Caravan_Booking数据表

da = New SqlDataAdapter（" SELECT * FROM Caravan_Booking"，Cn）

da.Fill（dsFullBooking，" dtCaraBooking"）

''创建Room_booking数据表

da =新SqlDataAdapter（" SELECT * FROM Room_Booking"，Cn）

da.Fill（dsFullBooking，" dtRoomBooking"）

''创建Meal_Booking数据表

da = New SqlDataAdapter（" SELECT * FROM Meal_Bookings"，Cn）

da.Fill（dsFullBooking，" dtMealBooking"）


''---------- Relationships

Dim rel_Client_Booking As New DataRelation（" dsFullBooking"，dsFullBooking.Tables

（" dtClient"）。Columns（" ClientID"），dsFullBooking.Tables（" ; dtBooking"）。列（" ClientI D"））dsFullBooking.Relations.Add（rel_Client_Booking）


Dim rel_Booking_CaraBook As N ew DataRelation（" dsFullBooking"，dsFullBooking.Tables

（" dtBooking"）。Columns（" BookingID"），dsFullBooking.Tables（" dtCaraBooking"）。Columns

（" BookingID"））

dsFullBooking.Relations.Add（rel_Booking_CaraBook）

Dim rel_Booking_RoomBook As New DataRelation（" dsFullBooking"，dsFullBooking.Tables

（" dtBooking"）。列（" BookingID"），dsFullBooking.Tables（" dtRoomBooking"）。列

（" BookingID"））


dsFullBooking.Relations.Add（rel_Booking_RoomBook）


''声明datarelation的列（复合键）

Dim RoomBookColumns（4）As DataColumn

Dim MealBookColumns（4）As DataColumn


RoomBookColumns（0）= dsFullBooking.Tables（" dtRoomBooking"）。列（Boo kingID）

RoomBookColumns（1）= dsFullBooking.Tables（" dtRoomBooking"）。Colu mns（Roo mID）

RoomBookColumns（2）= dsFullBooking.Tables（" dtRoomBooking"）。列（" Roo mDt"）

RoomBookColumns（3 ）= dsFullBooking.Tables（" dtRoomBooking"）。列（" Req _Session"）

MealBookColumns（0）= dsFullBooking.Tables（" dtMealBooking"）。列（" ; Boo kingID"）

MealBookColumns（1）= dsFullBooking.Tables（" dtMealBooking"）。Columns（" Roo mID"）

MealBookColumns（2）= dsFullBooking .Tables（" dtMealBooking"）。列（" Roo mDt"）

MealBookColumns（3）= dsFullBooking.Tables（" dtMealBooking"）。Columns（" Req _Session"）


Dim rel_RoomBook_MealBook As New DataRelation（" myRelationName"，RoomBookColumns，

MealBookColumns，True）

dsFullBooking.Relations.Add（rel_RoomBook_MealBook ）

感谢任何帮助

解决方案

你好翡翠，


你和我一起检查了所有的名字，比如BookingID这主要是一个案例

我做错了。


VB在这种情况下也是大小写的感觉


Cor

Hi Cor


我检查了所有coloumn名称，它们都匹配到我的数据库中的内容！

我不确定的是，如果我需要使用SQLDataReader放置单个值到文本框中。这是最简单/最好的方法吗？


这是我在网上找到的为组合框添加值的代码。我为我的目的修改了它


这是正确的吗？

你好Cor，


我检查了所有列标题，它们是正确的！

我的语法是否正确？我用一个网络示例来获取我根据自己的需求量身定制的代码。


顺便说一句，请不要阅读我的帖子，因为我偶然发布在这里。 ：o）

Hi, I am trying to create a dataset with 6 tables and 5 relationships created between them. I am creating it in the Form_Load event. However i keep getting the following error...

An unhandled exception of type ''System.ArgumentNullException'' occurred in system.data.dll
Additional information: ''column'' argument cannot be null.

The code stops on this line...
Dim rel_Booking_CaraBook As New DataRelation("dsFullBooking", dsFullBooking.Tables("dtBooking").Columns("Booking ID"), dsFullBooking.Tables("dtCaraBooking").Columns("Boo kingID"))

Does anyone know what im doin wrong??
Here is my full code....

Dim dsFullBooking As New DataSet()
''create the customer datatable
da = New SqlDataAdapter("SELECT * FROM Client", Cn)
da.Fill(dsFullBooking, "dtClient")
''create the booking datatable
da = New SqlDataAdapter("SELECT * FROM Booking", Cn)
da.Fill(dsFullBooking, "dtBooking")
''create the Caravan_Booking datatable
da = New SqlDataAdapter("SELECT * FROM Caravan_Booking", Cn)
da.Fill(dsFullBooking, "dtCaraBooking")
''create the Room_booking datatable
da = New SqlDataAdapter("SELECT * FROM Room_Booking", Cn)
da.Fill(dsFullBooking, "dtRoomBooking")
''create the Meal_Booking datatable
da = New SqlDataAdapter("SELECT * FROM Meal_Bookings", Cn)
da.Fill(dsFullBooking, "dtMealBooking")

''----------Relationships
Dim rel_Client_Booking As New DataRelation("dsFullBooking", dsFullBooking.Tables
("dtClient").Columns("ClientID"), dsFullBooking.Tables("dtBooking").Columns("ClientI D")) dsFullBooking.Relations.Add(rel_Client_Booking)

Dim rel_Booking_CaraBook As New DataRelation("dsFullBooking", dsFullBooking.Tables
("dtBooking").Columns("BookingID"), dsFullBooking.Tables("dtCaraBooking").Columns
("BookingID"))
dsFullBooking.Relations.Add(rel_Booking_CaraBook)
Dim rel_Booking_RoomBook As New DataRelation("dsFullBooking", dsFullBooking.Tables
("dtBooking").Columns("BookingID"), dsFullBooking.Tables("dtRoomBooking").Columns
("BookingID"))

dsFullBooking.Relations.Add(rel_Booking_RoomBook)

''Declare the Columns for the datarelation (for compound keys)
Dim RoomBookColumns(4) As DataColumn
Dim MealBookColumns(4) As DataColumn

RoomBookColumns(0) = dsFullBooking.Tables("dtRoomBooking").Columns("Boo kingID")
RoomBookColumns(1) = dsFullBooking.Tables("dtRoomBooking").Columns("Roo mID")
RoomBookColumns(2) = dsFullBooking.Tables("dtRoomBooking").Columns("Roo mDt")
RoomBookColumns(3) = dsFullBooking.Tables("dtRoomBooking").Columns("Req _Session")

MealBookColumns(0) = dsFullBooking.Tables("dtMealBooking").Columns("Boo kingID")
MealBookColumns(1) = dsFullBooking.Tables("dtMealBooking").Columns("Roo mID")
MealBookColumns(2) = dsFullBooking.Tables("dtMealBooking").Columns("Roo mDt")
MealBookColumns(3) = dsFullBooking.Tables("dtMealBooking").Columns("Req _Session")

Dim rel_RoomBook_MealBook As New DataRelation("myRelationName", RoomBookColumns,
MealBookColumns, True)
dsFullBooking.Relations.Add(rel_RoomBook_MealBook)
any help is appreciated

解决方案

Hi Jade,

Did you check all the names like BookingID with me this is mostly a case
error that I did make.

VB is in this case also case sensetive

Cor

Hi Cor

I have checked all the coloumn names and they all match up to what is in my database!
What i wasnt sure about is if i need to use the SQLDataReader to place a single value into a textbox. Is this the easiest/best way to do this?

This is the code i found on the net to add values to a combobox. I modified it for my purposes

Is it correct?

Hi Cor,

I have checked all the column headings and they are correct!!!
Is my syntax correct? I used a web example to get this code which i tailored to my own needs.

btw, do not read my post below this as i posted here by accident. :o)

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