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目前我正在处理的是 XML 的类型：XML FILE

参考 XML 文件，我想检查一个节点，如果没有找到该节点，我必须将该节点附加到文件中。我尝试了以下代码：

 private void button12_Click(object sender, EventArgs e)
    {
     //   XmlNodeList func_name_value = doc.GetElementsByTagName("FUNCTION-NAME-VALUE");
        XmlNodeList list_def_ref = doc.GetElementsByTagName("DEFINITION-REF");
        foreach (XmlNode nodeDef in list_def_ref)
        {
            if (nodeDef.InnerText == "/AUTOSAR/Com/ComConfig/ComSignal")
                {
                    if (nodeDef.ParentNode.HasChildNodes)
                    {
                        XmlNodeList list = nodeDef.ParentNode.ChildNodes;
                        foreach (XmlNode node in list)
                        {
                            if (node.Name == "PARAMETER-VALUES")
                            {
                                XmlNodeList param_list = node.ChildNodes;
                                foreach (XmlNode paramNode in param_list)
                                {
                                    if (paramNode.Name == "FUNCTION-NAME-VALUE")
                                    {
                                        XmlNodeList func_child_list = paramNode.ChildNodes;
                                        foreach (XmlNode funChild in func_child_list)
                                        {
                                            if (funChild.Name == "DEFINITION-REF")
                                            {
                                                string tout = "/AUTOSAR/Com/ComConfig/ComSignal/ComTimeoutNotification";
                                                string comnotify = "/AUTOSAR/Com/ComConfig/ComSignal/ComNotification";
                                                string invalid = "/AUTOSAR/Com/ComConfig/ComSignal/ComInvalidNotification";
                                                if (funChild.InnerText != tout)
                                                {
                                                    if (funChild.InnerText != comnotify)
                                                    {
                                                        //ADD ComInvalidNotification tags
                                                        XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
                                                        paramNode.AppendChild(newNode);
                                                        XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
                                                        XmlAttribute attr = doc.CreateAttribute("DEST");
                                                        attr.Value = "FUNCTION-NAME-DEF";
                                                        defRefNode.Attributes.SetNamedItem(attr);
                                                        newNode.AppendChild(defRefNode);
                                                        XmlNode val = doc.CreateElement("VALUE");
                                                        val.InnerText = "ComInvalidNotification";//ComInvalidNotification + shortName ;
                                                        newNode.AppendChild(val);
                                                    }
                                                    else
                                                    {
                                                        //ADD ComNotification tags
                                                        XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
                                                        paramNode.AppendChild(newNode);
                                                        XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
                                                        XmlAttribute attr = doc.CreateAttribute("DEST");
                                                        attr.Value = "FUNCTION-NAME-DEF";
                                                        defRefNode.Attributes.SetNamedItem(attr);
                                                        newNode.AppendChild(defRefNode);
                                                        XmlNode val = doc.CreateElement("VALUE");
                                                        val.InnerText = "ComNotification Node";//ComNotification + shortName;
                                                        newNode.AppendChild(val);
                                                    }
                                                }
                                                else
                                                {
                                                    //ADD ComTimeOutNotification tags
                                                    XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
                                                    paramNode.AppendChild(newNode);
                                                    XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
                                                    XmlAttribute attr = doc.CreateAttribute("DEST");
                                                    attr.Value = "FUNCTION-NAME-DEF";
                                                    defRefNode.Attributes.SetNamedItem(attr);
                                                    newNode.AppendChild(defRefNode);
                                                    XmlNode val = doc.CreateElement("VALUE");
                                                    val.InnerText = "ComTimeoutNotification node";//ComInvalidNotification + shortName;
                                                    newNode.AppendChild(val);
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

        doc.Save(openFileDialog1.FileName);

我得到的错误是：元素列表已更改。枚举操作无法继续。

在第一次执行 foreach 循环后，我收到了这个错误，我应该如何克服这个错误？

4

1 回答 1

2

你在这里有两个问题：

  1. 您正在修改您的XmlNodeList集合，同时迭代它们。Microsoft 的标准做法是在迭代期间修改集合时引发异常，例如，请参阅以下文档IEnumerator.MoveNext：

    例外

    InvalidOperationException：在创建枚举器后修改了集合。

    为避免此异常，您可以手动使用for循环和索引XmlNodeList，或快照到静态List<T>并迭代该.

  2. 您正在搜索名为<DEFINITION-REF>and的 XML 节点<FUNCTION-NAME-VALUE>，但您也在创建具有此名称的节点。这意味着您在迭代早期创建的节点可能会在迭代后期找到，从而导致递归创建更多节点。我想你不想要这个。如果我的估计是正确的，您应该对所有满足您的搜索条件的节点进行快照，然后遍历快照，如下所示：

    private static void AddMissingNodes(XmlDocument doc)
{
    var query = from nodeDef in doc.GetElementsByTagName("DEFINITION-REF").Cast<XmlNode>()
                where nodeDef.InnerText == "/AUTOSAR/Com/ComConfig/ComSignal"
                from nodeDefSibling in nodeDef.ParentNode.ChildNodes.Cast<XmlNode>()
                where nodeDefSibling.Name == "PARAMETER-VALUES"
                from paramNode in nodeDefSibling.ChildNodes.Cast<XmlNode>()
                where paramNode.Name == "FUNCTION-NAME-VALUE"
                select new
                {
                    paramNode = paramNode,
                    func_child_list = (from funChild in paramNode.ChildNodes.Cast<XmlNode>()
                                      where funChild.Name == "DEFINITION-REF"
                                       select funChild).ToList() // Snapshot func_child_list by calling ToList()
                };

    foreach (var paramNodeAndFuncChildren in query.ToList()) // Snapshot everything by calling ToList()
        foreach (var funChild in paramNodeAndFuncChildren.func_child_list)
            AddMissingNodes(doc, paramNodeAndFuncChildren.paramNode, funChild);

}

private static void AddMissingNodes(XmlDocument doc, XmlNode paramNode, XmlNode funChild)
{
    string tout = "/AUTOSAR/Com/ComConfig/ComSignal/ComTimeoutNotification";
    string comnotify = "/AUTOSAR/Com/ComConfig/ComSignal/ComNotification";
    string invalid = "/AUTOSAR/Com/ComConfig/ComSignal/ComInvalidNotification";
    if (funChild.InnerText != tout)
    {
        if (funChild.InnerText != comnotify)
        {
            //ADD ComInvalidNotification tags
            XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
            paramNode.AppendChild(newNode);
            XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
            XmlAttribute attr = doc.CreateAttribute("DEST");
            attr.Value = "FUNCTION-NAME-DEF";
            defRefNode.Attributes.SetNamedItem(attr);
            newNode.AppendChild(defRefNode);
            XmlNode val = doc.CreateElement("VALUE");
            val.InnerText = "ComInvalidNotification";//ComInvalidNotification + shortName ;
            newNode.AppendChild(val);
        }
        else
        {
            //ADD ComNotification tags
            XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
            paramNode.AppendChild(newNode);
            XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
            XmlAttribute attr = doc.CreateAttribute("DEST");
            attr.Value = "FUNCTION-NAME-DEF";
            defRefNode.Attributes.SetNamedItem(attr);
            newNode.AppendChild(defRefNode);
            XmlNode val = doc.CreateElement("VALUE");
            val.InnerText = "ComNotification Node";//ComNotification + shortName;
            newNode.AppendChild(val);
        }
    }
    else
    {
        //ADD ComTimeOutNotification tags
        XmlNode newNode = doc.CreateElement("FUNCTION-NAME-VALUE");
        paramNode.AppendChild(newNode);
        XmlNode defRefNode = doc.CreateElement("DEFINITION-REF");
        XmlAttribute attr = doc.CreateAttribute("DEST");
        attr.Value = "FUNCTION-NAME-DEF";
        defRefNode.Attributes.SetNamedItem(attr);
        newNode.AppendChild(defRefNode);
        XmlNode val = doc.CreateElement("VALUE");
        val.InnerText = "ComTimeoutNotification node";//ComInvalidNotification + shortName;
        newNode.AppendChild(val);
    }
}

    然后，如果我计算之前和之后的 XML 节点数：

        var fileName = @"D:\Temp\Question36740480\autosar_ecucvalues_Fx4_L.xml";
    var newFileName = @"D:\Temp\Question36740480\autosar_ecucvalues_Fx4_L_NEW.xml";

    var doc = new XmlDocument();
    doc.Load(fileName);

    int countBefore = doc.SelectNodes("descendant::*").Count;

    AddMissingNodes(doc);

    int countAfter = doc.SelectNodes("descendant::*").Count;

    Debug.WriteLine(string.Format("Added {0} nodes", countAfter - countBefore));

    doc.Save(newFileName);

    Debug.WriteLine("Wrote: " + newFileName);

    我看到 342 个节点被添加到XmlDocument.

于 2016-04-20T18:51:10.270 回答