LINQ to XML 中的 InvalidCastException

发布于 2024-11-07 12:59:38 字数 683 浏览 0 评论 0原文

我正在使用 LINQ to XML 从资源中获取一些数据，这里我有一个函数，我在其中获取一些值，然后创建一个新对象（类型翻译），因此当我调用该函数时，我会得到一个翻译对象。现在我有了这段代码：

     Public Shared Function RetrieveTranslation(ByVal file As String) As List(Of clsTranslation)
    Dim valuetrans = From vl In XElement.Load(file).Elements("data") Select (New clsTranslation With {.Filename = file, .Value = vl.Element("value").Value, .TranslationId = vl.Attribute("name").Value})
    Return valuetrans
End Function

问题是，使用这段代码我得到了这个错误：无法将“WhereSelectEnumerableIterator2[System.Xml.Linq.XElement,clsTranslation]”类型的对象转换为“System.Collections.Generic.List1[clsTranslation]”类型。

你知道它的投射方法吗？预先感谢，

阿方索。

原文

I am using LINQ to XML to take some data from resources , and here I have a function, where I take some values and then I create a new object (Type Translation), so when I call the function I get a Translation object. By now I have this code:

     Public Shared Function RetrieveTranslation(ByVal file As String) As List(Of clsTranslation)
    Dim valuetrans = From vl In XElement.Load(file).Elements("data") Select (New clsTranslation With {.Filename = file, .Value = vl.Element("value").Value, .TranslationId = vl.Attribute("name").Value})
    Return valuetrans
End Function

The problem is that with this code I got this error:
Unable to cast object of type 'WhereSelectEnumerableIterator2[System.Xml.Linq.XElement,clsTranslation]' to type 'System.Collections.Generic.List1[clsTranslation]'.

Do you know the way to cast it?
Thanks in advance,

Alfonso.

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⊕婉儿 2024-11-14 12:59:38

如果您在打开 Option Strict 的情况下进行编译，您就会在编译时发现这一点。

您无需强制转换它 - 您对结果调用 ToList()，以从 IEnumerable 创建一个 List 。

（我还建议您放弃 cls 前缀；它违反了 .NET 命名约定。）

这样会留下：

Public Shared Function RetrieveTranslation(ByVal file As String) _
        As List(Of Translation)
    Return (From vl In XElement.Load(file).Elements("data") _
            Select (New Translation With { _
                               .Filename = file, _
                               .Value = vl.Element("value").Value, _
                               .TranslationId = vl.Attribute("name").Value}) _
           ).ToList()
End Function

If you were compiling with Option Strict on, you'd have found this out at compile time.

You don't cast it - you call ToList() on the result, to create a List<clsTranslation> from the IEnumerable<clsTranslation>.

(I'd also advise you to ditch the cls prefix; it goes against the .NET naming conventions.)

That would leave:

Public Shared Function RetrieveTranslation(ByVal file As String) _
        As List(Of Translation)
    Return (From vl In XElement.Load(file).Elements("data") _
            Select (New Translation With { _
                               .Filename = file, _
                               .Value = vl.Element("value").Value, _
                               .TranslationId = vl.Attribute("name").Value}) _
           ).ToList()
End Function

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