Question

我试图将多年前在VB6中创建的这个函数转换为C＃，但我不知道如何去做。在这个VB6代码中，我对如何在{C＃中使用MSXML2.DOMDocument40作为参数感到困惑。我确定它会要求使用XmlDocument。

Private Function m_LoadXML(xmlDoc As MSXML2.DOMDocument40, xmlRoot As MSXML2.IXMLDOMElement, strXMLScript As String) As Boolean
    On Error GoTo Proc_Error

    Dim blnResult As Boolean
    Dim strMsg As String

    blnResult = False

    Set xmlDoc = New MSXML2.DOMDocument40

    If xmlDoc.Load(strXMLScript) Then
        Set xmlRoot = SafeElementNode(xmlDoc, mcstrXmlNodeRoot)

        If Not xmlRoot Is Nothing Then
            blnResult = True
        Else
            strMsg = "Invalid XML database definition file " & strXMLScript
            RaiseEvent ErrorMessage(strMsg)
        End If
    Else
        strMsg = "Can not load XML database definition file " & strXMLScript
        RaiseEvent ErrorMessage(strMsg)
    End If

    Proc_Exit:
        On Error Resume Next
        m_LoadXML = blnResult
        Exit Function

    Proc_Error:
        RaiseEvent ErrorMessage(Error)
        Resume Proc_Exit
End Function

Public Function SafeElementNode( _
        vxmlDocumentOrElement As MSXML2.IXMLDOMNode, _
        vstrQueryString As String _
    ) As MSXML2.IXMLDOMNode
        On Error Resume Next

        Set SafeElementNode = 
    vxmlDocumentOrElement.selectSingleNode(vstrQueryString)
End Function

以下是我到目前为止所提出的：

private bool m_LoadXML(XmlElement xmlRoot, string strXMLScript)
{
    bool blnResult = false;
    string strMsg;

    var xmlDoc = new XmlDocument();

    try
    {
        xmlDoc.Load(strXMLScript);
        xmlRoot = xmlDoc.DocumentElement;

        if (xmlRoot != null) blnResult = true;
        else
        {
            strMsg = "Invalid XML database definition file " + strXMLScript;
            MessageBox.Show(strMsg);
        }
    }
    catch (Exception)
    {
        strMsg = "Can not load XML database definition file " + strXMLScript;
        MessageBox.Show(strMsg);
        throw;
    }

    return blnResult;
}

Answer 1

我认为这应该有用。您拥有的现有代码并未将xmlRoot变量声明为out参数，因此您最终会得到一个空根元素。

private bool m_LoadXML(out XmlElement xmlRoot, string strXMLScript)
{
    bool blnResult = false;
    string strMsg;

    var xmlDoc = new XmlDocument();

    try
    {
        xmlDoc.Load(strXMLScript);
        xmlRoot = xmlDoc.DocumentElement;

        if (xmlRoot != null) blnResult = true;
        else
        {
            strMsg = "Invalid XML database definition file " + strXMLScript;
            MessageBox.Show(strMsg);
        }
    }
    catch (Exception)
    {
        strMsg = "Can not load XML database definition file " + strXMLScript;
        MessageBox.Show(strMsg);
        throw;
    }

    return blnResult;
}

private void TestLoadXml(string xmlFile)
{
    XmlElement elem;
    var result = m_LoadXML(out elem, xmlFile);
}

与其他评论员所说的一样，XDocument非常适合使用，值得一试。

将XML操作代码从VB6转换为C＃

1 个答案: