Question

我的基于DataGridView的应用程序有问题。将记录添加到网格后，如果我随后尝试更新或删除新记录，则会出现以下相应错误。并发冲突：UpdateCommand影响了预期的1条记录中的0条。并发冲突：DeleteCommand影响了预期的1条记录中的0条。在RowValidated事件中强制保存数据集。

Private Sub uxGrid_RowValidated(sender As Object, e As DataGridViewCellEventArgs) Handles uxGrid.RowValidated
    If IsDGVRowDirty(sender, e.RowIndex) Then
        Save()
    End If
End Sub

Private Sub Save()
    Const procName As String = "Save"
    Try
        _Logger.SendLog(Me.Name & "." & procName & " - Saving alarm definition data.", NLog.LogLevel.Trace)
        _myAlarmDefinitionMngr.Save(_myDataSet)
        _Logger.SendLog(Me.Name & "." & procName & " - Alarm definition data has been saved.", NLog.LogLevel.Trace)
    Catch ex As Exception
        MsgBox("There was a problem whilst saving your changes.  Please reload the form and try again.  " & vbCrLf & vbCrLf & ex.Message, MsgBoxStyle.Critical)
        _Logger.SendLog(ex.Message & ".  Thrown in module " & Me.Name.ToString & "." & procName, NLog.LogLevel.Error, ex)
    Finally
    End Try
End Sub

客户端应用程序位于一个相对简单的3层架构设计之上，与Oracle 11后端通信，在这种情况下包含元素AlarmDefinitionManager.vb，AlarmDefinitionDB.vb，AlarmDefinition.vb。

Public Function Save(ByVal myDataSet As DataSet) As Integer
    Dim myOda As OracleDataAdapter
    Dim myConnection As New OracleConnection
    Dim myCommand As OracleCommand = Nothing
    Dim myDataAdapter As OracleDataAdapter
    Dim myBuilder As OracleCommandBuilder
    Dim sqlStatement As String

    myConnection = New OracleConnection
    myConnection.ConnectionString = _connectStr
    sqlStatement = "SELECT ID, LEGENDID, STATUSID, STATUSTYPEID, DIGITALSET FROM P_TBL_ALARMDEF"
    If myDataSet.HasChanges Then
        Try
            myOda = New OracleDataAdapter(sqlStatement, myConnection)
            myBuilder = New OracleCommandBuilder(myOda)
            myOda.SelectCommand = New OracleCommand(sqlStatement, myConnection)
            myOda.Update(myDataSet, "AlarmDefinition")
            myDataSet.AcceptChanges()
            myConnection.Close()
        Catch ex As Exception
            Throw
        Finally
            myCommand = Nothing
            myDataAdapter = Nothing
            myBuilder = Nothing
           CType(myConnection, IDisposable).Dispose()
        End Try
    End If
End Function

我对情况的理解是我需要刷新网格中的数据源，以便它反映所做的更改。为了实现这一点，我希望通过将刷新过程挂钩到datagridview中的事件来刷新网格。然而，我尝试过的事件似乎都没有奏效。到目前为止尝试了每个事件，我收到的错误是，不允许在事件中刷新数据源。经过反思，这看似合乎逻辑是否有与datagridview关联的事件可用于强制刷新数据源？

Answer 1

在验证行时，您不应尝试保存数据集。对数据集进行更改，然后将数据源设置为null，并将数据源重新连接回网格以强制刷新。

我个人不喜欢对数据网格进行更改。我更喜欢编辑datagrid外的行，并向SQL发送UPDATE cmd，然后刷新我的网格。我可以更好地控制对网格所做的更改。

Answer 2

排序我的问题。每行更改都直接保存到RowValidated事件中的数据库中。

DataGridView - 更新或删除新记录时的并发问题

2 个答案: