VB中dataView.Table.GetChanges().Rows.Count 未将对象引用到实例

当视图没有发生变化时 dataView.Table.GetChanges().Rows.Count 就未将对象引用到实例，当修改dataview后错误提示消失！
怎么判断getchanges().rows.count 为nothing或者说在没有修改的时候不报错

代码如下：

Private Sub grdshrView_BeforeLeaveRow(ByVal sender As System.Object, ByVal e As DevExpress.XtraGrid.Views.Base.RowAllowEventArgs) Handles grdshrView.BeforeLeaveRow

MessageBox.Show(dataHandleShr.Dv.Table.GetChanges().Rows.Count) '没有修改dataview时错误

If OperationType = Framework.OperateType.Edit Or OperationType = Framework.OperateType.Add And dataHandleShr.Dv.Table.GetChanges().Rows.Count > 0 Then
ShrYZ()
End If
End Sub

[解决办法]
修改datatable后，记得调用下acceptchange方法。