Question

我刚刚将此代码移动到一个新的sub并尝试运行它并获得了tite中所述的异常。

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解决以保持功能？

感谢。

Answer 1

在这一行

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

您正在尝试阅读名为PanelIP的字段，但您的查询无法检索它。
这导致IndexOutOfRangeException，因为在内部，读者试图将该名称（PanelIP）转换为检索字段列表中的位置，并且当名称不存在时，则假定该位置为 - 1。当然-1是检索字段列表中的无效索引

说，让我们来看看您的查询以及如何解决它。

我希望您的TableName变量受到严格控制，因为用户可以传递该变量中的任何内容，这可能会导致称为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，因为参数只能用于不是字段或表名的值

Answer 2

您的查询广告中没有variableName参数，您尝试添加一个值。这会导致IndexOutOfRangeException。

您可以包含参数或只删除

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

类型＆＃39; System.IndexOutOfRangeException＆＃39;的第一次机会异常发生在System.Data.dll中

2 个答案: