Question

我用C ++编写了一个应用程序，它从类成员中生成一个XML文件。现在我想再次读取生成的文件，并将所有属性和值保存回C ++类。

我的XML编写器（写得很成功）：

void TDescription::WriteXml( XmlWriter^ writer )
{
    writer->WriteStartElement( "Description" );
    writer->WriteAttributeString( "Version", m_sVersion );
    writer->WriteAttributeString( "Author", m_sAuthor );
    writer->WriteString( m_sDescription );
    writer->WriteEndElement();
}

我的XML阅读器（导致异常）：

void TDescription::ReadXml( XmlReader^ reader )
{
    reader->ReadStartElement( "Description" );
    m_sVersion = reader->GetAttribute( "Version" );
    m_sAuthor = reader->GetAttribute( "Author" );
    m_sDescription = reader->ReadString();
    reader->ReadEndElement();
}

我生成的XML文件：

<?xml version="1.0" encoding="utf-8"?>
<root Name="database" Purpose="try" Project="test">
     <!--Test Database-->
     <Description Version="1.1B" Author="it">primary</Description>
</root>

以下是读者引起的例外情况：

An unhandled exception of type 'System.InvalidOperationException' occurred in System.Xml.dll

Additional information: There is an error in XML document (2, 2).

代码有什么问题？我认为XmlReader方法没有以正确的方式使用！？

由于答案1，我更改了代码：

reader->ReadStartElement( "root" );
reader->ReadStartElement( "Description" );
m_sVersion = reader->GetAttribute( "Version" );
m_sAuthor = reader->GetAttribute( "Author" );
m_sDescription = reader->ReadString();
reader->ReadEndElement();
reader->ReadEndElement();

现在，我没有得到例外，m_sDescription获得了正确的值，但 m_sVersion 和 m_sAuthor 仍然是空。

Answer 1

您必须致电ReadStartElement以获取＆＃34; root＆＃34;在那之前。

reader->ReadStartElement( "root" );     
reader->ReadStartElement( "Description" );

修改：读取属性

reader->ReadToFollowing( "Description" );
reader->MoveToFirstAttribute();
String ^ m_sVersion = reader->Value;     
reader->MoveToNextAttribute();
String ^ m_sAuthor = reader->Value;           
String ^ m_sDescription = reader->ReadString();     
reader->ReadEndElement();

调用XmlReader :: ReadStartElement时抛出InvalidOperationException

1 个答案: