vb.net - 如何将 VB 6 中的代码转换为 VB.NET？

Question

我有机会在迁移项目（VB 到 VB.NET）中工作。我对 RecordSet 功能感到困惑。在我们的项目中，我们根据场景使用 DataReader。但是在像 dsr.EOF 这样的循环案例中。

  Dim recordset As dao.RecordSet
If recordset .EOF Then
       '    '    msgbox "Please enter some number ", vbOKOnly, "Number Not Found"
       '    '    txtAdd.SetFocus
       '    '    Exit Sub
End If

如何将其转换为 VB.NET？我们需要写 If Not reader.Read 或 If reader.Read。

有什么可以帮助我的吗？

Answer 1

我想你可能会追求的是以下

Dim reader As IDataReader
' <fill the reader with your query via an IDbCommand>
Dim dataFound As Boolean = false

Using reader = command.ExecuteQuery()
    While reader.Read()
        ' <perform your data processing here>
        dataFound = True
    End While

    If dataFound = False Then
        ' <Here you do your processing for the case where data was not found.>
    End If
End Using

或者，如果您只关注一行数据，那么我们有：

Dim reader As IDataReader
' <fill the reader with your query via an IDbCommand>

Using reader = command.ExecuteQuery()
    If reader.Read() Then
        ' <perform your data processing here>
    Else
        ' <Here you do your processing for the case where data was not found.>
    End While
End Using