我正在尝试在代码中创建一个包含 datagridviews 的主从表单。SELECT/fill 部分工作正常，但我遇到了 UPDATE/INSERT/DELETE 问题（这应该在表单关闭时自动发生）。以下代码给出了错误：
Update 要求 UpdateCommand 有一个连接对象。UpdateCommand 的 Connection 属性尚未初始化。
上.Update线。
我尝试将连接移出 GetData() 过程，但这不是答案。
我应该做什么？
代码：
Imports System.Data
Imports System.Data.OleDb
Public Class TestMe2
Private lblSelector As New Label
Private cbSelector As New ComboBox
Private bsSelector As New BindingSource
Private daMaster As New OleDbDataAdapter
Private dgMaster As New DataGrid
Private bsMaster As New BindingSource
Private dgLookup As New DataGrid
Private bsLookups As New BindingSource
Private dsGFF As New DataSet
Private cnn As New OleDbConnection
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Me.Controls.Add(lblSelector)
lblSelector.Location = New System.Drawing.Point(0, 0)
lblSelector.Text = "FileType"
Me.Controls.Add(cbSelector)
cbSelector.Location = New System.Drawing.Point(Me.lblSelector.Width, 0)
Me.Controls.Add(dgMaster)
dgMaster.Location = New System.Drawing.Point(0, cbSelector.Height)
dgMaster.Height = 300
dgMaster.Width = 2000
Me.Controls.Add(dgLookup)
dgLookup.Location = New System.Drawing.Point(0, cbSelector.Height + dgMaster.Height)
dgLookup.Height = 100
dgLookup.Width = 1000
End Sub
Private Sub TestMe2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
bsSelector.DataSource = dsGFF
cbSelector.DataSource = bsSelector
bsMaster.DataSource = dsGFF
dgMaster.DataSource = bsMaster
bsLookups.DataSource = dsGFF
dgLookup.DataSource = bsLookups
GetData()
bsMaster.DataSource = bsSelector
bsMaster.DataMember = "FileTypesToGFFTranslator"
bsLookups.DataSource = bsMaster
bsLookups.DataMember = "GFFTranslatorToTranslations"
'dgMaster.autoresizecolumns()
End Sub
Private Sub GetData()
Dim command As New OleDbCommand
Dim parameter As New OleDbParameter
' where's the data?
Dim cnnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\GFFTranslator.accdb"
cnn = New OleDb.OleDbConnection(cnnString)
' set up up the selector
Dim daSelector As New OleDbDataAdapter("SELECT FileType FROM vwFileTypeSelection", cnn)
daSelector.Fill(dsGFF, "vwFileTypeSelection")
bsSelector.DataSource = dsGFF
bsSelector.DataMember = "vwFileTypeSelection"
cbSelector.ValueMember = "FileType"
cbSelector.DisplayMember = "FileType"
daSelector.Fill(dsGFF)
' set up the master
daMaster = New OleDbDataAdapter("SELECT * FROM GFFTranslator", cnn)
daMaster.Fill(dsGFF, "GFFTranslator")
daMaster.UpdateCommand = New OleDbCommand("UPDATE GFFTRanslator" & _
" SET FileType = ?" & _
" , FieldPosition = ?" & _
" , FieldType = ?" & _
" , StartRepeatingSection = ?" & _
" , FileTypeIdentifier = ?" & _
" , Flag = ?" & _
" , DataStart = ?" & _
" , DataLength = ?" & _
" , NextLine = ?" & _
" , Lookup = ?" & _
" , Title = ?" & _
" , ExtraInfo = ?" & _
" WHERE FileType = ?" & _
" AND FieldPosition = ? ;")
daMaster.UpdateCommand.Parameters.Add("@FileType", OleDbType.VarChar, 255, "FileType")
daMaster.UpdateCommand.Parameters.Add("@FieldPosition", OleDbType.Integer, 4, "FieldPosition")
daMaster.UpdateCommand.Parameters.Add("@FieldType", OleDbType.VarChar, 255, "FieldType")
daMaster.UpdateCommand.Parameters.Add("@StartRepeatingSection", OleDbType.Boolean, 1, "StartRepeatingSection")
daMaster.UpdateCommand.Parameters.Add("@FileTypeIdentifier", OleDbType.Boolean, 1, "FileTypeIdentifier")
daMaster.UpdateCommand.Parameters.Add("@Flag", OleDbType.Boolean, 1, "Flag")
daMaster.UpdateCommand.Parameters.Add("@DataStart", OleDbType.Integer, 5, "DataStart")
daMaster.UpdateCommand.Parameters.Add("@DataLength", OleDbType.Integer, 5, "DataLength")
daMaster.UpdateCommand.Parameters.Add("@NextLine", OleDbType.Boolean, 1, "NextLine")
daMaster.UpdateCommand.Parameters.Add("@Lookup", OleDbType.Boolean, 1, "Lookup")
daMaster.UpdateCommand.Parameters.Add("@Title", OleDbType.VarChar, 255, "Title")
daMaster.UpdateCommand.Parameters.Add("@ExtraInfo", OleDbType.VarChar, 255, "ExtraInfo")
' set up the lookup
Dim daLookup As New OleDbDataAdapter("SELECT * FROM Translations", cnn)
daLookup.Fill(dsGFF, "Translations")
' link everything together
Try
Dim drMaster As New DataRelation("FileTypesToGFFTranslator" _
, dsGFF.Tables("vwFileTypeSelection").Columns("FileType") _
, dsGFF.Tables("GFFTranslator").Columns("FileType"))
dsGFF.Relations.Add(drMaster)
Dim dcMaster As DataColumn() = New DataColumn() {dsGFF.Tables("GFFTranslator").Columns("FileType"), dsGFF.Tables("GFFTranslator").Columns("FieldType")}
Dim dcLookup As DataColumn() = New DataColumn() {dsGFF.Tables("Translations").Columns("FileType"), dsGFF.Tables("Translations").Columns("FieldType")}
Dim drLookup As New DataRelation("GFFTranslatorToTranslations" _
, dcMaster _
, dcLookup)
dsGFF.Relations.Add(drLookup)
Catch ex As Exception
MessageBox.Show("Error: " & ex.Message)
End Try
End Sub
Protected Overrides Sub Finalize()
Me.Validate()
Me.daMaster.Update(dsGFF.Tables("GFFTranslator"))
Me.dsGFF.AcceptChanges()
MyBase.Finalize()
End Sub
End Class