从SelectTable中选择创建1DataTable [英] Create 1DataTable from a Select from DataTable

问题描述

我在尝试从DataGrid（dgOrders）的

选择中创建（临时）DataTable时遇到问题。

dtOrdDetails被声明为Public DataTable


Sub是：


Dim stFilter as String

Dim OrdersRows（）as DataRow

''如果OrderNo =""然后订单是ASN

如果gstOrderNo =""然后

''ASN选择


否则

''OrderNo选择


''为dtOrderDetails创建结构

dtOrderDetails = dsPOs.Tables（" PODetails"）

dtOrderDetails.Clear（）


''设置过滤器 - 列[PONo] =选择的订单号

stFilter =" PONo =" &安培; gstOrderNo

OrdersRows = dsPOs.Tables（" PODetails"）。选择（stFilter）


''填充dtOrderDetails

For i = 0到OrdersRows.GetUpperBound（0）

dtOrderDetails.ImportRow（OrderRows（i））

下一个我


结束如果


我的问题是OrderRows的行数为0但我可以在那里看到有效的

记录。

I还试过：

stFilter =" PONo =''" &安培; gstOrderNo& "''"

stFilter =" PONO =" &安培; gstOrderNo

stFilter =" PONO =" &安培; gstOrderNo& "''"

实际别名字段名称是PONo但我注意到DB2数据库返回

列大写。

字段类型是十进制8,0

我可以单步执行DataTablePODetails并且可以看到PONo =所选的

过滤编号。


感谢您的帮助，


Doug

解决方案

道格，


你有什么理由不使用currencymanager.position

起点并使用数据网格中的底层表格来完成新数据表的

填充，直到达到要执行的行为止？


Cor

" Doug Bell" < dug @ bigpond>

..

我在尝试从
选择创建（临时）DataTable时遇到问题一个DataGrid（dgOrders）。

dtOrdDetails被声明为Public DataTable



Dim stFilter as String
Dim OrdersRows （）as DataRow
''如果OrderNo =""然后订单是ASN
如果gstOrderNo =""然后
''ASN选择

其他
''OrderNo Selection

''为dtOrderDetails创建结构
dtOrderDetails = dsPOs.Tables（ PODetails）
dtOrderDetails.Clear（）

''设置过滤器 - 列[PONo] =选择的订单号
stFilter =" PONo =" &安培; gstOrderNo
OrdersRows = dsPOs.Tables（" PODetails"）。选择（stFilter）

''填充dtOrderDetails
对于i = 0到OrdersRows.GetUpperBound（0）
dtOrderDetails.ImportRow（OrderRows（i））
接下来我

结束如果

我的问题是OrderRows的行数为0但我可以那里看到有效的
记录。
我也尝试过：
stFilter =" PONo =''" &安培; gstOrderNo& "''"
stFilter =" PONO =" &安培; gstOrderNo
stFilter =" PONO =" &安培; gstOrderNo& "''"
实际别名字段名称是PONo，但我注意到DB2数据库
返回
列大写。
字段类型是十进制8,0

我可以逐步浏览DataTablePODetails。并且可以看到PONO =
选择的过滤器编号。

感谢您的帮助，

Doug

Doug，

我的问题是OrderRows的行数为0，但我可以在那里看到有效的
记录。
dtOrderDetails = dsPOs.Tables（" PODetails"）
dtOrderDetails.Clear（）
您刚刚清除了dsPOs.Tables（" PODetails"）！


DataTable是一种引用类型，当您将一个引用

变量/属性分配给另一个时，您正在制作该引用的副本。

变量（dtOrderDetails& dsPOs.Tables（" PODetails"））指的是堆上的确切

相同的DataTable对象。如果您在一个变量上调用Clear，那么

也会在另一个变量上调用clear。


而不是上面两行，您可以使用以下内容单行：

dtOrderDetails = dsPOs.Tables（" PODetails"）。Clone（）


这会创建DataTable结构的空副本。如果您使用

..Copy（）（如您在前面的帖子中提到的那样），您将获得结构

&您的DataTable的数据。


您的其余代码应该可以使用。我通常使用For Each代替

For，主要是为了避免off by one。问题，但这不应该导致你的代码有问题。


对于OrdersRows中的每行作为DataRow

dtOrderDetails。 ImportRow（行）

下一页我


希望这有帮助

Jay


道格贝尔 <挖@的BigPond>在消息中写道

新闻：％2 **************** @ TK2MSFTNGP14.phx.gbl ...
我遇到了问题尝试从DataGrid（dgOrders）的
选择创建一个（临时）DataTable。

dtOrdDetails被声明为Public DataTable

Sub是：将OrdersRows（）调暗为DataRow
''如果OrderNo =""然后订单是ASN
如果gstOrderNo =""然后
''ASN选择

其他
''OrderNo Selection

''为dtOrderDetails创建结构
dtOrderDetails = dsPOs.Tables（ PODetails）
dtOrderDetails.Clear（）

''设置过滤器 - 列[PONo] =选择的订单号
stFilter =" PONo =" &安培; gstOrderNo
OrdersRows = dsPOs.Tables（" PODetails"）。选择（stFilter）

''填充dtOrderDetails
对于i = 0到OrdersRows.GetUpperBound（0）
dtOrderDetails.ImportRow（OrderRows（i））
接下来我

结束如果

我的问题是OrderRows的行数为0但我可以那里看到有效的
记录。
我也尝试过：
stFilter =" PONo =''" &安培; gstOrderNo& "''"
stFilter =" PONO =" &安培; gstOrderNo
stFilter =" PONO =" &安培; gstOrderNo& "''"
实际别名字段名称是PONo，但我注意到DB2数据库
返回
列大写。
字段类型是十进制8,0

我可以逐步浏览DataTablePODetails。并且可以看到PONO =
选择的过滤器编号。

感谢您的帮助，

Doug

面团，


我从周杰伦的消息中得知我在下面做的是什么

你想做什么


\\\这个样本需要一个包含2个datagrids的表单

Private Sub Form1_Load（ByVal sender As Object，_

ByVal e As System.EventArgs）处理MyBase.Load

DataGrid1.DataSource = createDS.Tables（0）

Dim mynewtable As DataTable = _

DirectCast（DataGrid1.DataSource，DataTable）.Clone

Dim myrows As DataRow（）= DirectCast（DataGrid1.DataSource，_

DataTable ）。选择（" Numbers> 5"）

For each dr As DataRow in myrows

mynewtable.ImportRow（dr）

Next

DataGrid2.DataSource = mynewtable

End Sub

''Bellow仅用于在数据中创建数据表et b / b
Public Function createDS（）As DataSet

Dim ds As New DataSet

Dim dt As New DataTable

ds.Tables.Add（dt）

dt.Columns.Add（" Numbers"，GetType（System.Int32））

dt.Columns.Add（"字符）

对于i as Integer = 0到10

ds.Tables（0）.Rows.Add（ds.Tables（0）.NewRow）

ds.Tables（0）.Rows（i）.ItemArray = _

（新对象（）{i.ToString，ChrW（i + 65）}）

下一页

返回ds

结束功能

///

我希望这有帮助吗？


Cor


" Doug Bell" < dug @ bigpond>

..

我在尝试从
选择创建（临时）DataTable时遇到问题一个DataGrid（dgOrders）。

dtOrdDetails被声明为Public DataTable



Dim stFilter as String
Dim OrdersRows （）as DataRow
''如果OrderNo =""然后订单是ASN
如果gstOrderNo =""然后
''ASN选择

其他
''OrderNo Selection

''为dtOrderDetails创建结构
dtOrderDetails = dsPOs.Tables（ PODetails）
dtOrderDetails.Clear（）

''设置过滤器 - 列[PONo] =选择的订单号
stFilter =" PONo =" &安培; gstOrderNo
OrdersRows = dsPOs.Tables（" PODetails"）。选择（stFilter）

''填充dtOrderDetails
对于i = 0到OrdersRows.GetUpperBound（0）
dtOrderDetails.ImportRow（OrderRows（i））
接下来我

结束如果

我的问题是OrderRows的行数为0但我可以那里看到有效的
记录。
我也尝试过：
stFilter =" PONo =''" &安培; gstOrderNo& "''"
stFilter =" PONO =" &安培; gstOrderNo
stFilter =" PONO =" &安培; gstOrderNo& "''"
实际别名字段名称是PONo，但我注意到DB2数据库
返回
列大写。
字段类型是十进制8,0

我可以逐步浏览DataTablePODetails。并且可以看到PONO =
选择的过滤器编号。

感谢您的帮助，

Doug

Hi,
I am having problems trying to create a (temporary) DataTable from a
selection from a DataGrid (dgOrders).

dtOrdDetails is declared as a Public DataTable

Sub is:

Dim stFilter as String
Dim OrdersRows() as DataRow
''If OrderNo = "" then Order is an ASN
If gstOrderNo = "" Then
''ASN Selection

Else
''OrderNo Selection

''Create structure for dtOrderDetails
dtOrderDetails = dsPOs.Tables("PODetails")
dtOrderDetails.Clear()

''Set Filter - Column [PONo] = Selected Order No.
stFilter = "PONo = " & gstOrderNo
OrdersRows = dsPOs.Tables("PODetails").Select(stFilter)

''Populate dtOrderDetails
For i = 0 to OrdersRows.GetUpperBound(0)
dtOrderDetails.ImportRow(OrderRows(i))
Next i

End If

My problem is that OrderRows has a Row Count of 0 and yet I can see valid
records there.
I have also tried:
stFilter = "PONo = ''" & gstOrderNo & "''"
stFilter = "PONO = " & gstOrderNo
stFilter = "PONO = " & gstOrderNo & "''"
Actual Alias Field Name is PONo but I have noticed the DB2 Database returns
Columns capitalised.
Field Type is Decimal 8,0

I can step through the DataTable "PODetails" and can see PONo = the Selected
Filter Number.

Thanks for any help,

Doug

解决方案

Doug,

Is there any reason that don''t you use the currencymanager.position for your
start point and use the underlaying table from the datagrid to do the
filling of your new datatable until the rows to do are reached?

Cor
"Doug Bell" <dug@bigpond>
..

Hi,
I am having problems trying to create a (temporary) DataTable from a
selection from a DataGrid (dgOrders).

dtOrdDetails is declared as a Public DataTable

Sub is:

Dim stFilter as String
Dim OrdersRows() as DataRow
''If OrderNo = "" then Order is an ASN
If gstOrderNo = "" Then
''ASN Selection

Else
''OrderNo Selection

''Create structure for dtOrderDetails
dtOrderDetails = dsPOs.Tables("PODetails")
dtOrderDetails.Clear()

''Set Filter - Column [PONo] = Selected Order No.
stFilter = "PONo = " & gstOrderNo
OrdersRows = dsPOs.Tables("PODetails").Select(stFilter)

''Populate dtOrderDetails
For i = 0 to OrdersRows.GetUpperBound(0)
dtOrderDetails.ImportRow(OrderRows(i))
Next i

End If

My problem is that OrderRows has a Row Count of 0 and yet I can see valid
records there.
I have also tried:
stFilter = "PONo = ''" & gstOrderNo & "''"
stFilter = "PONO = " & gstOrderNo
stFilter = "PONO = " & gstOrderNo & "''"
Actual Alias Field Name is PONo but I have noticed the DB2 Database
returns
Columns capitalised.
Field Type is Decimal 8,0

I can step through the DataTable "PODetails" and can see PONo = the
Selected
Filter Number.

Thanks for any help,

Doug

Doug,

My problem is that OrderRows has a Row Count of 0 and yet I can see valid
records there. dtOrderDetails = dsPOs.Tables("PODetails")
dtOrderDetails.Clear() You just cleared dsPOs.Tables("PODetails")!

DataTable is a reference type, when you assign one reference
variable/property to another you are making a copy of the reference. Both
variables (dtOrderDetails & dsPOs.Tables("PODetails")) refer to the exact
same DataTable object on the heap. If you call Clear on the one variable you
are also calling clear on the other variable.

Instead of the above two lines, you can use the following single line:
dtOrderDetails = dsPOs.Tables("PODetails").Clone()
This creates an empty copy of the structure of your DataTable. If you used
..Copy() (as Cor mentioned in your earlier post) you would get the structure
& data of your DataTable.

The rest of your code should work. I normally use a For Each instead of a
For, mostly to avoid "off by one" problems, however that should not cause a
problem with your code.

For Each row As DataRow in OrdersRows
dtOrderDetails.ImportRow(row)
Next i

Hope this helps
Jay

"Doug Bell" <dug@bigpond> wrote in message
news:%2****************@TK2MSFTNGP14.phx.gbl... Hi,
I am having problems trying to create a (temporary) DataTable from a
selection from a DataGrid (dgOrders).

dtOrdDetails is declared as a Public DataTable

Sub is:

Dim stFilter as String
Dim OrdersRows() as DataRow
''If OrderNo = "" then Order is an ASN
If gstOrderNo = "" Then
''ASN Selection

Else
''OrderNo Selection

''Create structure for dtOrderDetails
dtOrderDetails = dsPOs.Tables("PODetails")
dtOrderDetails.Clear()

''Set Filter - Column [PONo] = Selected Order No.
stFilter = "PONo = " & gstOrderNo
OrdersRows = dsPOs.Tables("PODetails").Select(stFilter)

''Populate dtOrderDetails
For i = 0 to OrdersRows.GetUpperBound(0)
dtOrderDetails.ImportRow(OrderRows(i))
Next i

End If

My problem is that OrderRows has a Row Count of 0 and yet I can see valid
records there.
I have also tried:
stFilter = "PONo = ''" & gstOrderNo & "''"
stFilter = "PONO = " & gstOrderNo
stFilter = "PONO = " & gstOrderNo & "''"
Actual Alias Field Name is PONo but I have noticed the DB2 Database
returns
Columns capitalised.
Field Type is Decimal 8,0

I can step through the DataTable "PODetails" and can see PONo = the
Selected
Filter Number.

Thanks for any help,

Doug

Dough,

I get from the message from Jay the idea that what I did below is something
as you wanted to do

\\\This sample needs a form with 2 datagrids
Private Sub Form1_Load(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
DataGrid1.DataSource = createDS.Tables(0)
Dim mynewtable As DataTable = _
DirectCast(DataGrid1.DataSource, DataTable).Clone
Dim myrows As DataRow() = DirectCast(DataGrid1.DataSource, _
DataTable).Select("Numbers > 5")
For Each dr As DataRow In myrows
mynewtable.ImportRow(dr)
Next
DataGrid2.DataSource = mynewtable
End Sub
''Bellow only to create a datatable in a dataset
Public Function createDS() As DataSet
Dim ds As New DataSet
Dim dt As New DataTable
ds.Tables.Add(dt)
dt.Columns.Add("Numbers", GetType(System.Int32))
dt.Columns.Add("Characters")
For i As Integer = 0 To 10
ds.Tables(0).Rows.Add(ds.Tables(0).NewRow)
ds.Tables(0).Rows(i).ItemArray = _
(New Object() {i.ToString, ChrW(i + 65)})
Next
Return ds
End Function
///
I hope this helps?

Cor

"Doug Bell" <dug@bigpond>
..

Hi,
I am having problems trying to create a (temporary) DataTable from a
selection from a DataGrid (dgOrders).

dtOrdDetails is declared as a Public DataTable

Sub is:

Dim stFilter as String
Dim OrdersRows() as DataRow
''If OrderNo = "" then Order is an ASN
If gstOrderNo = "" Then
''ASN Selection

Else
''OrderNo Selection

''Create structure for dtOrderDetails
dtOrderDetails = dsPOs.Tables("PODetails")
dtOrderDetails.Clear()

''Set Filter - Column [PONo] = Selected Order No.
stFilter = "PONo = " & gstOrderNo
OrdersRows = dsPOs.Tables("PODetails").Select(stFilter)

''Populate dtOrderDetails
For i = 0 to OrdersRows.GetUpperBound(0)
dtOrderDetails.ImportRow(OrderRows(i))
Next i

End If

My problem is that OrderRows has a Row Count of 0 and yet I can see valid
records there.
I have also tried:
stFilter = "PONo = ''" & gstOrderNo & "''"
stFilter = "PONO = " & gstOrderNo
stFilter = "PONO = " & gstOrderNo & "''"
Actual Alias Field Name is PONo but I have noticed the DB2 Database
returns
Columns capitalised.
Field Type is Decimal 8,0

I can step through the DataTable "PODetails" and can see PONo = the
Selected
Filter Number.

Thanks for any help,

Doug

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