我遇到了一个问题,我使用数据适配器更新然后重新填充数据表。调用填充方法后,行被复制。一个 ID 具有正确的(新)ID,而另一个 ID 显示 -1。下面的代码完美运行,是我希望我的更复杂代码执行的更简单的形式。考虑以下内容:
Imports WindowsApplication1.testDataSet
Imports WindowsApplication1.testDataSetTableAdapters
Imports System.Data.OleDb
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim DA As New testTableAdapter
Dim DT As New testDataTable
DA.Fill(DT)
Dim NR As testRow = DT.Rows.Add
NR.SomeText = "Test"
Dim DA2 As New OleDbDataAdapter("SELECT * FROM test", _
DA.Connection.ConnectionString)
Dim CB As New OleDbCommandBuilder(DA2)
DA2.Update(DT)
DA.Fill(DT)
For Each R As testRow In DT.Rows
Debug.Print(R.ID)
Next
End Sub
End Class
上面的代码完美运行。它们的键列不显示 -1,没有重复项。现在考虑我的应用程序中的以下代码,该代码导致重复行,其中键列在最后一个之后导致 -1 LoadLoadNumbers()
。
Dim AccountLoans As IEnumerable(Of LoanNumbersRow) = _
From L As LoanNumbersRow In LoanNumbers _
Select L Where L.AccountID = ID
If Not frmFindLoans.IsDisposed AndAlso _
frmFindLoans.DialogResult = Windows.Forms.DialogResult.OK Then
For Each L As LoanNumbersRow In AccountLoans
If (From R As DataGridViewRow In frmFindLoans.dgvLoans.Rows _
Select R Where R.Cells("LoanNumber").Value = L.LoanNumber).Count = 0 Then
If L.IsWhenDeletedNull Then
L.WhenDeleted = Now
L.DeletedBy = UserName()
End If
End If
Next
Dim NewLoan As LoanNumbersRow
Dim FindLoan As IEnumerable(Of LoanNumbersRow)
For Each R As DataGridViewRow In frmFindLoans.dgvLoans.Rows
FindLoan = From L As LoanNumbersRow In LoanNumbers.Rows _
Select L Where L.LoanNumber = R.Cells("LoanNumber").Value And _
L.AccountID = ID
If FindLoan.Count = 0 Then
NewLoan = LoanNumbers.Rows.Add
NewLoan.AccountID = Acc.AccountID
NewLoan.LoanNumber = R.Cells("LoanNumber").Value
NewLoan.LoanBusinessName = R.Cells("LoanBusiness").Value
NewLoan.LoanBorrower = R.Cells("LoanBorrower").Value
NewLoan.AddedBy = UserName()
NewLoan.WhenAdded = Now
End If
Next
Try
Dim CB As New OleDbCommandBuilder(LoanNumbersAdapter)
LoanNumbersAdapter.Update(LoanNumbers)
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error saving loan number data")
Exit Sub
End Try
If Not LoadLoanNumbers() Then Exit Sub
End If
来自模块的其他变量等:
Public LoanNumbersAdapter As OleDbDataAdapter
Public LoanNumbers As New LoanNumbersDataTable
Public Sub InitializeAdapters()
LoanNumbersAdapter = New OleDbDataAdapter( _
"SELECT * FROM LoanNumbers WHERE WhenDeleted IS NULL ORDER BY WhenAdded DESC", AccountingConn)
End Sub
Public Function LoadData(ByVal DA As OleDbDataAdapter, ByVal DT As DataTable) As Boolean
Try
DA.Fill(DT)
Return True
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error loading the " & DT.TableName & " table")
Return False
End Try
End Function
Public Function LoadLoanNumbers() As Boolean
Return LoadData(LoanNumbersAdapter, LoanNumbers)
End Function
为什么顶部的简单测试可以正常工作,但我的实际应用程序在键列上创建了带有 -1 的重复行?我想我可以在更新后填充之前清除数据表,但是一旦它开始变成一个大表,它不会陷入困境吗?*顺便说一句:数据库是 MS 访问,它是 .NET 3.5