绑定列表不同步 [英] bindinglist not synching

问题描述

VS 2005


我有一类BindingList（T）用作查询的数据源

组合框。组合框用于查找采购订单的条款。


当我在Winform上实现它时，组合框不会与

基础数据同步，即条款描述没有显示条款

数字。


组合框确实在下拉框中显示描述，因此它们是

被填入绑定列表，他们只是不同步

基础数据。


任何人都可以看到是什么错了？


瑞克


**** combox盒就像这样连接***

cbTerms。 DisplayMember =" Name"

cbTerms.ValueMember =" Num"

Dim bs As LookupNVP = New LookupNVP（LookupNVP.listType。条款，fMain.conn）


cbTerms.DataSource = bs


cbTerms.DataBindings.Clear（）


cbTerms.DataBindings.Add（" SelectedValue"，PObind，" Termsnum"）

**** class fo r bindinglist ****


Public Class LookupNVP


继承BindingList（of nvp）


公共枚举列表类型


条款


Shipvia


结束枚举


公共类nvp


私有_name为字符串


私有_num为整数


Public ReadOnly属性名称（）为字符串


获取


返回_name


结束获取


结束物业


Public ReadOnly Property Num（）作为整数


获取


返回_num


结束获取


结束物业


Private Sub New（）


End Sub


Public Sub New（ByVal newValue As Integer，ByVal newName As String）


_name = newName


_num = newValue


End Sub


结束班


Public Sub New（ByVal list as lis tType，ByVal conn As FbConnection）


MyBase.New（）


Dim sql As String


选择案例列表


案例列表类型.Shipvia


sql ="选择SHIPVIANUM，METHOD || ''[''|| SHIPVIANUM || '']''' _


& 来自SHIPVIA的方法订购


案例列表类型。条款


sql ="选择TERMSNUM，DESCRIPTION || ''[''|| TERMSNUM || '']''' _


& 来自TERMS排序说明


结束选择


如果sql什么都没有那么返回


Dim cmd As FbCommand = New FbCommand（sql，conn）


''Dim reader As FbDataReader


试试


conn.Open（）


使用reader作为FbDataReader =

cmd.ExecuteReader（CommandBehavior.CloseConnection）


虽然读者阅读


Me.Add（新nvp（reader.GetInt32（0），reader.GetString（1）））


结束时


reader.Close（）


结束使用


最后


conn.Close（）


结束尝试


End Sub


结束类

解决方案

覆盖LookupNVP类中的ToString方法。


那么当你发布你的代码时，如果你将它粘贴到记事本中，那么

将它复制并粘贴到你的帖子中，它会l保持其间距，并且更容易阅读。阅读越容易，有人就越有可能帮助你了。


Robin S.

---- -----------------------


" Rick" < Ri ** @ LakeValleySeed.com写信息

新闻：％2 **************** @ TK2MSFTNGP04.phx.gbl ...

VS 2005

我有一类BindingList（T）用作查询的数据源

组合框。组合框用于查找采购订单的条款。


当我在Winform上实现它时，组合框不会与

基础数据同步，即条款描述没有显示条款

数字。


组合框确实在下拉框中显示描述，因此它们是

被填入绑定列表，他们只是不同步

基础数据。


任何人都可以看到是什么错了？


瑞克


**** combox盒就像这样连接***

cbTerms。 DisplayMember =" Name"

cbTerms.ValueMember =" Num"

Dim bs As LookupNVP = New LookupNVP（LookupNVP.listType。条款，fMain.conn）


cbTerms.DataSource = bs


cbTerms.DataBindings.Clear（）


cbTerms.DataBindings.Add（" SelectedValue"，PObind，" Termsnum"）


****类为bi ndinglist ****


Public Class LookupNVP


继承BindingList（of nvp）


公共枚举列表类型


条款


Shipvia


结束枚举

公共类nvp


私有_name为字符串


私有_num为整数


Public ReadOnly属性名称（）为字符串


获取


返回_name


结束获取


结束物业


Public ReadOnly Property Num（）as Integer


获取


返回_num


结束获取


结束物业


Private Sub New（）


End Sub


Public Sub New（ByVal newValue As Integer，ByVal newName As String）


_name = newName


_num = newValue


End Sub


结束类


Public Sub New（ByVal list as listType，ByVal conn As FbConnecti on）


MyBase.New（）


Dim sql As String


选择案例列表


案例listType.Shipvia


sql ="选择SHIPVIANUM，METHOD || ''[''|| SHIPVIANUM || '']''' _


& 来自SHIPVIA的方法订购


案例列表类型。条款


sql ="选择TERMSNUM，DESCRIPTION || ''[''|| TERMSNUM || '']''' _


& 来自TERMS排序说明


结束选择


如果sql什么都没有那么返回


Dim cmd As FbCommand = New FbCommand（sql，conn）


''Dim reader As FbDataReader


试试


conn.Open（）


使用reader作为FbDataReader =

cmd.ExecuteReader（CommandBehavior.CloseConnection）


虽然读者阅读


Me.Add（新nvp（reader.GetInt32（0），reader.GetString（1）））


结束时


reader.Close（）


结束使用


最后


conn.Close（）


结束尝试


End Sub


结束班

感谢笔记本提示。


我覆盖了ToString方法，但仍然没有快乐。另外是********

以下。


我做错了什么？


公共类LookupNVP

继承BindingList（of nvp）


Public Enum listType

条款

Shipvia

结束枚举


公共类nvp

私有_name为字符串

私有_num为整数


Public ReadOnly属性名称（）为字符串

获取

返回_name

结束获取< br $>
结束物业

公共只读物业数量（）为整数

获取

返回_num

结束获取

结束物业


私人子新（）

结束子


Public Sub New（ByVal newValue As Integer，ByVal newName As String）

_name = newName

_num = newValue

End Sub


''************************************* *******

Public Overrides Function ToString（）As String

返回我。姓名

结束功能


''************************* ********************


结束班级


Public Sub New（ ByVal list作为listType，ByVal conn As FbConnection）

MyBase.New（）

Dim sql As String

选择案例列表

Case listType.Shipvia

sql ="选择SHIPVIANUM，METHOD || ''[''|| SHIPVIANUM ||

'']''" _

& 按SHIPVIA方式订购

案例清单类型。条款

sql ="选择TERMSNUM，DESCRIPTION || ''[''|| TERMSNUM ||

'']''" _

& 来自TERMS排序说明

结束选择


如果sql什么都没有那么返回


Dim cmd作为FbCommand = New FbCommand（sql，conn）

''Dim reader As FbDataReader

试试

conn.Open（）

使用reader作为FbDataReader =

cmd.ExecuteReader（CommandBehavior.CloseConnection）

虽然reader.Read

Me.Add（New nvp（reader.GetInt32（0），reader.GetString（1）））

结束时

reader.Close（）

结束使用


最后

conn.Close（）

结束尝试


End Sub


结束班


" RobinS" < Ro **** @ NoSpam.yah.nonewrote in message

news：6f ************************ ******@comcast.com。 ..

覆盖LookupNVP类中的ToString方法。


顺便提一下，当你发布代码时，如果你将它粘贴到记事本中，然后将
复制并粘贴到你的帖子中，它将保留其间距，并且更容易阅读。阅读越容易，有人就越有可能帮助你。


Robin S.

将你的nvp类移出lookupNvp类。


Public Class LookupNVP

继承BindingList（of nvp）

....

结束班


公共舱NVP

....

（ToString在这里）

结束类


将数据库的读数放在LookupNVP中，并将每个NVP对象添加到

你的清单。


Robin S.

----------------- ----------

< Rick" < Ri ** @ LakeValleySeed.com写信息

news：eQ ************** @ TK2MSFTNGP03.phx.gbl ...
< blockquote class =post_quotes>
感谢笔记本提示。


我超越了ToString方法，但仍然没有快乐。下面是

********。


我做错了什么？


公共类LookupNVP

继承BindingList（of nvp）


Public Enum listType

条款

Shipvia

结束枚举


公共类nvp

私有_name为字符串

私有_num为整数


Public ReadOnly属性名称（）为字符串

获取

返回_name

结束获取< br $>
结束物业

公共只读物业数量（）为整数

获取

返回_num

结束获取

结束物业


私人子新（）

结束子


Public Sub New（ByVal newValue As Integer，ByVal newName As String）

_name = newName

_num = newValue

结束子


''************************ ********************

Public Overrides Function ToString（）As String

Return Me.Name

结束功能


''**************************** *****************


结束班


Public Sub New（ByVal list As listType，ByVal conn As FbConnection）

MyBase.New（）

Dim sql As String

选择案例列表

案例listType.Shipvia

sql ="选择SHIPVIANUM，METHOD || ''[''|| SHIPVIANUM ||

'']''" _

& 按SHIPVIA方式订购

案例清单类型。条款

sql ="选择TERMSNUM，DESCRIPTION || ''[''|| TERMSNUM ||

'']''" _

& 来自TERMS排序说明

结束选择


如果sql什么都没有那么返回


Dim cmd作为FbCommand = New FbCommand（sql，conn）

''Dim reader As FbDataReader

试试

conn.Open（）

使用reader作为FbDataReader =

cmd.ExecuteReader（CommandBehavior.CloseConnection）

虽然reader.Read

Me.Add（New nvp（reader.GetInt32（0），

reader.GetString（1）））

结束时

reader.Close（）

结束使用


最后

conn.Close（）

结束尝试


End Sub


结束班级


RobinS < Ro **** @ NoSpam.yah.nonewrote in message

news：6f ************************ ******@comcast.com。 ..

>覆盖LookupNVP类中的ToString方法。

顺便说一下，当你发布你的代码时，如果你粘贴了它进入记事本，然后将其复制并粘贴到您的帖子中，它将保留其间距，并且更易于阅读。阅读越容易，人们就越有可能帮助你。

Robin S.

VS 2005

I have a class of BindingList(of T) to use as a datasource for a lookup
combobox. The combobox is to lookup the Terms for a Purchase Order.

When I implement this on my Winform, the combobox does not synch with the
underlying data, i.e. the Terms description does not show for the terms
number.

The combobox does show the Descriptions in the drop-down box, so they are
being filled into the binding list, they just don''t synch with the
underlying data.

Can anyone see what is wrong?

Rick

**** combox box is connected like this ***
cbTerms.DisplayMember = "Name"

cbTerms.ValueMember = "Num"

Dim bs As LookupNVP = New LookupNVP(LookupNVP.listType.Terms, fMain.conn)

cbTerms.DataSource = bs

cbTerms.DataBindings.Clear()

cbTerms.DataBindings.Add("SelectedValue", PObind, "Termsnum")
**** class for bindinglist ****

Public Class LookupNVP

Inherits BindingList(Of nvp)

Public Enum listType

Terms

Shipvia

End Enum

Public Class nvp

Private _name As String

Private _num As Integer

Public ReadOnly Property Name() As String

Get

Return _name

End Get

End Property

Public ReadOnly Property Num() As Integer

Get

Return _num

End Get

End Property

Private Sub New()

End Sub

Public Sub New(ByVal newValue As Integer, ByVal newName As String)

_name = newName

_num = newValue

End Sub

End Class

Public Sub New(ByVal list As listType, ByVal conn As FbConnection)

MyBase.New()

Dim sql As String

Select Case list

Case listType.Shipvia

sql = "Select SHIPVIANUM, METHOD || '' ['' || SHIPVIANUM || '']'' " _

& "from SHIPVIA order by METHOD"

Case listType.Terms

sql = "Select TERMSNUM, DESCRIPTION || '' ['' || TERMSNUM || '']'' " _

& "from TERMS order by DESCRIPTION"

End Select

If sql Is Nothing Then Return

Dim cmd As FbCommand = New FbCommand(sql, conn)

''Dim reader As FbDataReader

Try

conn.Open()

Using reader As FbDataReader =
cmd.ExecuteReader(CommandBehavior.CloseConnection)

While reader.Read

Me.Add(New nvp(reader.GetInt32(0), reader.GetString(1)))

End While

reader.Close()

End Using

Finally

conn.Close()

End Try

End Sub

End Class

解决方案

Override the ToString method in your LookupNVP class.

By the way, when you post your code, if you paste it into Notepad, then
copy and paste it into your posting, it will retain its spacing, and be
easier to read. The easier it is to read, the more likely someone will help
you.

Robin S.
---------------------------

"Rick" <Ri**@LakeValleySeed.comwrote in message
news:%2****************@TK2MSFTNGP04.phx.gbl...

VS 2005

I have a class of BindingList(of T) to use as a datasource for a lookup
combobox. The combobox is to lookup the Terms for a Purchase Order.

When I implement this on my Winform, the combobox does not synch with the
underlying data, i.e. the Terms description does not show for the terms
number.

The combobox does show the Descriptions in the drop-down box, so they are
being filled into the binding list, they just don''t synch with the
underlying data.

Can anyone see what is wrong?

Rick

**** combox box is connected like this ***
cbTerms.DisplayMember = "Name"

cbTerms.ValueMember = "Num"

Dim bs As LookupNVP = New LookupNVP(LookupNVP.listType.Terms, fMain.conn)

cbTerms.DataSource = bs

cbTerms.DataBindings.Clear()

cbTerms.DataBindings.Add("SelectedValue", PObind, "Termsnum")
**** class for bindinglist ****

Public Class LookupNVP

Inherits BindingList(Of nvp)

Public Enum listType

Terms

Shipvia

End Enum

Public Class nvp

Private _name As String

Private _num As Integer

Public ReadOnly Property Name() As String

Get

Return _name

End Get

End Property

Public ReadOnly Property Num() As Integer

Get

Return _num

End Get

End Property

Private Sub New()

End Sub

Public Sub New(ByVal newValue As Integer, ByVal newName As String)

_name = newName

_num = newValue

End Sub

End Class

Public Sub New(ByVal list As listType, ByVal conn As FbConnection)

MyBase.New()

Dim sql As String

Select Case list

Case listType.Shipvia

sql = "Select SHIPVIANUM, METHOD || '' ['' || SHIPVIANUM || '']'' " _

& "from SHIPVIA order by METHOD"

Case listType.Terms

sql = "Select TERMSNUM, DESCRIPTION || '' ['' || TERMSNUM || '']'' " _

& "from TERMS order by DESCRIPTION"

End Select

If sql Is Nothing Then Return

Dim cmd As FbCommand = New FbCommand(sql, conn)

''Dim reader As FbDataReader

Try

conn.Open()

Using reader As FbDataReader =
cmd.ExecuteReader(CommandBehavior.CloseConnection)

While reader.Read

Me.Add(New nvp(reader.GetInt32(0), reader.GetString(1)))

End While

reader.Close()

End Using

Finally

conn.Close()

End Try

End Sub

End Class

Thanks for the notebook tip.

I overrode the ToString method, but still no joy. The addition is ********
below.

What did I do wrong?

Public Class LookupNVP
Inherits BindingList(Of nvp)

Public Enum listType
Terms
Shipvia
End Enum

Public Class nvp
Private _name As String
Private _num As Integer

Public ReadOnly Property Name() As String
Get
Return _name
End Get
End Property
Public ReadOnly Property Num() As Integer
Get
Return _num
End Get
End Property

Private Sub New()
End Sub

Public Sub New(ByVal newValue As Integer, ByVal newName As String)
_name = newName
_num = newValue
End Sub

''********************************************
Public Overrides Function ToString() As String
Return Me.Name
End Function

''*********************************************

End Class

Public Sub New(ByVal list As listType, ByVal conn As FbConnection)
MyBase.New()
Dim sql As String
Select Case list
Case listType.Shipvia
sql = "Select SHIPVIANUM, METHOD || '' ['' || SHIPVIANUM ||
'']'' " _
& "from SHIPVIA order by METHOD"
Case listType.Terms
sql = "Select TERMSNUM, DESCRIPTION || '' ['' || TERMSNUM ||
'']'' " _
& "from TERMS order by DESCRIPTION"
End Select

If sql Is Nothing Then Return

Dim cmd As FbCommand = New FbCommand(sql, conn)
''Dim reader As FbDataReader
Try
conn.Open()
Using reader As FbDataReader =
cmd.ExecuteReader(CommandBehavior.CloseConnection)
While reader.Read
Me.Add(New nvp(reader.GetInt32(0), reader.GetString(1)))
End While
reader.Close()
End Using

Finally
conn.Close()
End Try

End Sub

End Class

"RobinS" <Ro****@NoSpam.yah.nonewrote in message
news:6f******************************@comcast.com. ..

Override the ToString method in your LookupNVP class.

By the way, when you post your code, if you paste it into Notepad, then
copy and paste it into your posting, it will retain its spacing, and be
easier to read. The easier it is to read, the more likely someone will
help you.

Robin S.

Move your nvp class out of your lookupNvp class.

Public Class LookupNVP
Inherits BindingList(of nvp)
....
End Class

Public Class NVP
....
(ToString goes here)
End Class

Put the reading of the database in LookupNVP, and add each NVP object to
your list.

Robin S.
---------------------------
"Rick" <Ri**@LakeValleySeed.comwrote in message
news:eQ**************@TK2MSFTNGP03.phx.gbl...

Thanks for the notebook tip.

I overrode the ToString method, but still no joy. The addition is
******** below.

What did I do wrong?

Public Class LookupNVP
Inherits BindingList(Of nvp)

Public Enum listType
Terms
Shipvia
End Enum

Public Class nvp
Private _name As String
Private _num As Integer

Public ReadOnly Property Name() As String
Get
Return _name
End Get
End Property
Public ReadOnly Property Num() As Integer
Get
Return _num
End Get
End Property

Private Sub New()
End Sub

Public Sub New(ByVal newValue As Integer, ByVal newName As String)
_name = newName
_num = newValue
End Sub

''********************************************
Public Overrides Function ToString() As String
Return Me.Name
End Function

''*********************************************

End Class

Public Sub New(ByVal list As listType, ByVal conn As FbConnection)
MyBase.New()
Dim sql As String
Select Case list
Case listType.Shipvia
sql = "Select SHIPVIANUM, METHOD || '' ['' || SHIPVIANUM ||
'']'' " _
& "from SHIPVIA order by METHOD"
Case listType.Terms
sql = "Select TERMSNUM, DESCRIPTION || '' ['' || TERMSNUM ||
'']'' " _
& "from TERMS order by DESCRIPTION"
End Select

If sql Is Nothing Then Return

Dim cmd As FbCommand = New FbCommand(sql, conn)
''Dim reader As FbDataReader
Try
conn.Open()
Using reader As FbDataReader =
cmd.ExecuteReader(CommandBehavior.CloseConnection)
While reader.Read
Me.Add(New nvp(reader.GetInt32(0),
reader.GetString(1)))
End While
reader.Close()
End Using

Finally
conn.Close()
End Try

End Sub

End Class

"RobinS" <Ro****@NoSpam.yah.nonewrote in message
news:6f******************************@comcast.com. ..

>Override the ToString method in your LookupNVP class.

By the way, when you post your code, if you paste it into Notepad, then
copy and paste it into your posting, it will retain its spacing, and be
easier to read. The easier it is to read, the more likely someone will
help you.

Robin S.

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