System.Data.dll 中出现“System.IndexOutOfRangeException”类型的第一次机会异常

Question

我刚刚将此代码移动到一个新的 sub 并尝试运行它并获取异常，如 tite 中所述。

Public Sub LoadPanel(TableName As String)

    Debug.Print("LoadPanel:") 'name of module
    PushCallStack("LoadPanel") 'name of module

    Try
        Using dbConnection As New OleDbConnection(My.Settings.SMSA_databaseConnectionString)
            dbConnection.Open()
            Debug.Print("   dbConnection Success")

            Dim sqlcommand As String
            sqlcommand = "SELECT " & TableName & ".[PanelName] FROM  " & TableName & " WHERE (((" & TableName & ".[Owner])=" & CurrentClientID & ")) OR (((" & TableName & ".[Admin1])=" & CurrentClientID & ")) OR (((" & TableName & ".[Admin2])=" & CurrentClientID & ")) OR (((" & TableName & ".[Admin3])=" & CurrentClientID & ")) OR (((" & TableName & ".[Admin4])=" & CurrentClientID & "));"
            Debug.Print("   sqlcommand = " & sqlcommand)

            Dim getSomeData As New OleDbCommand(sqlcommand, dbConnection)
            With getSomeData
                .Parameters.AddWithValue("@variableName", "variableValue")
                Debug.Print("   Executing: getSomeData")
            End With
            Debug.Print("   Success: getSomeData")

            Debug.Print("   Try: DataReader")
            Using dataReader As OleDbDataReader = getSomeData.ExecuteReader
                Do While dataReader.Read
                    Dashboard_Client.ComboBox_PanelChoice.Items.Add(dataReader("PanelIP"))
                Loop
            End Using
        End Using

        PopCallStack() 'do not remove
    Catch ex As Exception
        GlobalErrHandler()
    End Try

    Debug.Print("LoadPanel End")

从调试面板：

LoadPanel:
dbConnection Success
Executing: getSomeData
Success: getSomeData
Try: DataReader
A first chance exception of type 'System.IndexOutOfRangeException' occurred in System.Data.dll

有没有办法解决此错误或进行变通以保留该功能？

谢谢。

Answer 1

在这一行

  Dashboard_Client.ComboBox_PanelChoice.Items.Add(dataReader("PanelIP"))

您正在尝试读取名为 PanelIP 的字段，但您的查询未检索到它。
这会导致IndexOutOfRangeException，因为在内部，读取器尝试将该名称（PanelIP）转换为检索到的字段列表中的位置，并且当名称不存在时，该位置被假定为-1。当然 -1 是检索到的字段列表中的无效索引

话虽如此，让我们来看看您的查询以及如何解决它。

我希望您可以严格控制 TableName 变量，因为用户可以在该变量中传递任何内容，这可能导致称为 Sql Injection 的危险情况

要修复的是缺少的字段，并将 currentClientID 的每个字符串连接更改为适当的参数

Dim sqlcommand = "SELECT " & TableName & ".[PanelName] " & _ 
                             TableName & ".[PanelID] " & _
                 " FROM  " & TableName & _ 
                 " WHERE (" & TableName & ".[Owner])=@ownerID) " & _
                 " OR    (" & TableName & ".[Admin1])=@clientID1) " & _
                 " OR    (" & TableName & ".[Admin2])=@clientID2) " & _   
                 " OR    (" & TableName & ".[Admin3])=@clientID3) " & _ 
                 " OR    (" & TableName & ".[Admin4])=@clientID4)"

Try
    Using dbConnection As New OleDbConnection(.....)
    Using getSomeData As New OleDbCommand(sqlcommand, dbConnection)
        dbConnection.Open()
        With getSomeData
            ' In oledb you need to add a parameter for every placeholder
            ' because the parameters are not recognized by name but by position
            .Parameters.Add("@ownerID", OleDbType.Integer).Value = currentClientID
            .Parameters.Add("@clientID1", OleDbType.Integer).Value = currentClientID
            .Parameters.Add("@clientID2", OleDbType.Integer).Value = currentClientID
            .Parameters.Add("@clientID3", OleDbType.Integer).Value = currentClientID
            .Parameters.Add("@clientID4", OleDbType.Integer).Value = currentClientID
        End With
        Using dataReader As OleDbDataReader = getSomeData.ExecuteReader
            Do While dataReader.Read
                Dashboard_Client.ComboBox_PanelChoice.Items.Add(dataReader("PanelIP"))
            Loop
        End Using
    End Using
    End Using

    PopCallStack()
Catch ex As Exception
    GlobalErrHandler()
End Try

遗憾的是，无法对 TableName 进行参数化，因为参数只能用于值，不能用于字段或表名

Answer 2

在您尝试添加值 1 的查询广告中没有 variableName 参数。这会导致 IndexOutOfRangeException。

你必须包含参数或者只是删除

.Parameters.AddWithValue("@variableName", "variableValue")