Question

嘿我正在尝试将以下代码从此网页转换为VB.NET

http://msdn.microsoft.com/en-us/magazine/cc163730.aspx

并且有一个转换成这样的方法

' Get the order from the session on demand
Private Shared Function GetOrderFromSession(ByVal i As Integer) As ShoppingCartOrder
    Dim session As HttpSessionState = HttpContext.Current.Session

    Dim ID As Integer = 0
    Dim quantity As Integer = 0

    ' note: For simplicity session key strings are dynamically 
    ' created——for performance reasons they should be precreated.
ID = CInt(session(ShoppingCartItemIDKeyBase + i))
quantity = CInt(session(ShoppingCartOrderQuantityKeyBase + i))

    Dim item As ShoppingCartItem = ShoppingCartItem.GetItem(ID)
    Return New ShoppingCartOrder(item, quantity)
End Function

但是在行周围得到错误

        ID = CInt(session(ShoppingCartItemIDKeyBase + i))
    quantity = CInt(session(ShoppingCartOrderQuantityKeyBase + i))

错误1重载解析失败，因为在没有缩小转换的情况下无法调用可访问的“Item”： 'Public Default Property Item（index As Integer）As Object'：参数匹配参数'index'从'Double'缩小为'Integer'。 'Public Default Property Item（name As String）As Object'：参数匹配参数'name'从'Double'缩小为'String'。

Answer 1

+运算符可用于字符串连接以及＆amp; VB.NET中的运算符，但＆符号是首选运算符。

可以肯定的是，您可以将它们切换为＆符号并查看错误是否仍然存在？ ShoppingCarItemIDKeyBase是一个字符串，我不确定+运算符是否强制字符串转换为数字，因为用户可以选择使用＆amp;。

ID = CInt(session(ShoppingCartItemIDKeyBase & i))
quantity = CInt(session(ShoppingCartOrderQuantityKeyBase & i))

Answer 2

这些变量中的一个或两个是十进制类型而不是整数：

ShoppingCartItemIDKeyBase
ShoppingCartOrderQuantityKeyBase

ASP.NET错误与会话密钥字符串

2 个答案: