在C#中优雅地处理XML文件中的验证错误

我想要执行的是遇到任何验证错误处理节点’A’或其子节点(XMLException和XmlSchemaValidationException)我想停止处理当前节点记录节点’A’的错误和XML并继续下一步节点’A’.

<Root>
  <A id="A1">
     <B Name="B1">
        <C>
          <D Name="ID" >
            <E>Test Text 1</E>
          </D>
        <D Name="text" >
          <E>Test Text 1</E>
        </D>        
      </C>
    </B>
  </A>
  <A id="A2">
    <B Name="B2">
      <C>
        <D Name="id" >
          <E>Test Text 3</E>
        </D>
        <D Name="tab1_id"  >
          <E>Test Text 3</E>
        </D>
        <D Name="text" >
          <E>Test Text 3</E>
        </D>
      </C>
    </B>
</Root>

我目前能够通过使用带有XMLReader的ValidationEventHandler从XmlSchemaValidationException中恢复,这会抛出我在XML Processing代码中处理的Exception.但是在某些情况下,触发XMLException会导致进程终止.

以下代码片段说明了我正在使用的当前结构;它很混乱,也欢迎代码改进建议.

// Setting up the XMLReader
    XmlReaderSettings settings = new XmlReaderSettings();
    settings.ConformanceLevel = ConformanceLevel.Auto;
    settings.IgnoreWhitespace = true;
    settings.CloseInput = true;
    settings.IgnoreComments = true;
    settings.ValidationType = ValidationType.Schema;
    settings.Schemas.Add(null,"schema.xsd");
    settings.ValidationEventHandler += new ValidationEventHandler(ValidationCallBack);
    XmlReader reader = XmlReader.Create("Sample.xml",settings);   
    // Processing XML
    while (reader.Read())
    if (reader.NodeType == XmlNodeType.Element)
       if (reader.Name.Equals("A"))
         processA(reader.ReadSubtree());            
    reader.Close(); 
   // Process Node A
   private static void processA(XmlReader A){
    try{
       // Perform some book-keeping 
       // Process Node B by calling processB(A.ReadSubTree())               
    }   
    catch (InvalidOperationException ex){

    }
    catch (XmlException xmlEx){

    } 
    catch (ImportException impEx){

    }
    finally{ if (A != null) A.Close(); }            
  }
  // All the lower level process node functions propagate the exception to caller.
  private static void processB(XmlReader B){
   try{
     // Book-keeping and call processC
   }
   catch (Exception ex){
    throw ex;
    }
   finally{ if (B != null) B.Close();}    
  } 
  // Validation event handler
  private static void ValidationCallBack(object sender,ValidationEventArgs e){
    String msg =  "Validation Error: " + e.Message +" at line " + e.Exception.LineNumber+
        " position number "+e.Exception.LinePosition;
    throw new ImportException(msg);
  }

遇到XMLSchemaValidationException时,finally块将调用close(),并且原始XMLReader位于子树的EndElement上,因此processA中的finally块将导致处理下一个节点A.

但是,遇到XMlException时,调用close方法不会将原始读取器放在子树的EndElement节点上,而是抛出InvalidOperationException.

我尝试使用诸如skip,ReadToXYZ()方法之类的方法,但是当在触发异常的任何节点上调用时,这些方法总是导致InvalidOperationException的XMLExcpetion.

以下是MSDN关于ReadSubTree方法的摘录.

When the new XmlReader has been
closed,the original XmlReader will be
positioned on the EndElement node of
the sub-tree. Thus,if you called the
ReadSubtree method on the start tag of
the book element,after the sub-tree
has been read and the new XmlReader
has been closed,the original
XmlReader is positioned on the end tag
of the book element.

注意：我不能使用.Net 3.5,但欢迎.Net 3.5建议.