德尔福 XE &OmniXML:使用 SelectNode()? [英] Delphi XE & OmniXML: Using SelectNode()?
问题描述
我将以下 XML 片段作为我正在使用最新 OmniXML 快照处理的较大 XML 文件的一部分:
I've got the following XML snippet as part of a larger XML file that I'm processing using the latest OmniXML snapshot:
<OrderRequestHeader>
<!-- snipped XML bits here -->
<ShipTo>
<Address addressID="">
<Name xml:lang="en">SOME COMPANY</Name>
<PostalAddress name="default">
<DeliverTo>John Doe</DeliverTo>
<Street>123 Any St</Street>
<City>Nowhere</City>
<State>AK</State>
<PostalCode>99999</PostalCode>
<Country isoCountryCode="US">United States</Country>
</PostalAddress>
<Email/>
<Phone>
<TelephoneNumber>
<CountryCode isoCountryCode=""/>
<AreaOrCityCode/>
<Number></Number>
</TelephoneNumber>
</Phone>
</Address>
</ShipTo>
<!-- more XML stuff follows -->
</OrderRequestHeader>
我目前有一个指向
节点的变量,并且想要选择
节点的内容.我正在使用以下代码,但是 Node2
即将出现 Nil
...
I've currently got a variable pointing to the <ShipTo>
node, and want to select the contents of the <Name>
node. I'm using the following code, but Node2
is coming up Nil
...
procedure ProcessXML;
var
Node1, Node2: IXMLNode;
begin
Node1 := FindNode(OrderHeader, 'ShipTo');
// the above is working. Node points to the <ShipTo> node
Node2 := SelectNode(Node1, 'Name');
// the above line doesn't work. Node2 is Nil
end;
为什么 Node2
Nil
?根据OmniXMLUtils.pas
中的帮助,SelectNode
将选择单个节点可能比低一级.肯定有一个
节点.即使尝试通过 XPathSelect(Node1, 'Name');
查找节点也会返回一个空列表.我以某种方式使用 OmniXML 是错误的吗?是否可以在不先选择 节点的情况下到达
节点?
Why is Node2
Nil
? According to the help in OmniXMLUtils.pas
, SelectNode
will select a single node possibly more than one level below. There's definitely a <Name>
node. Even trying to find the node via XPathSelect(Node1, 'Name');
returns an empty list. Am I using OmniXML wrong somehow? Is it possible to get to the <Name>
node without first selecting the <Address>
node?
推荐答案
SelectNode
工作正常,如果你把双斜线字符放在前面:
SelectNode
works fine, if you put double-slash characters in front:
var
FXMLDocument: IXMLDocument;
// Somewhere along the line
FXMLDocument := CreateXMLDocument
XMLLoadFromFile(FXMLDocument, 'WhateverFile.xml');
// or XMLLoadFromAnsiString(FXMLDocument, SomeStringVar);
var
QryNode, Node: IXMLNode;
begin
QryNode := FXMLDocument.DocumentElement;
Node := SelectNode(QryNode, 'ShipTo');
if Assigned(Node) then
begin
QryNode := SelectNode(Node, '//Name');
if Assigned(QryNode) then
ShowMessage('ShipTo Name is ' + QryNode.FirstChild.Text)
else
ShowMessage('Name not found');
end;
end;
如果您愿意,XPath 也可以正常工作:
If you prefer, XPath works fine as well:
implementation
var
FXMLDocument: IXMLDocument;
// Somewhere along the line
FXMLDocument := CreateXMLDocument
XMLLoadFromFile(FXMLDocument, 'WhateverFile.xml');
// or XMLLoadFromAnsiString(FXMLDocument, SomeStringVar);
function GetShipTo: string;
var
QryNode: IXMLNode;
Node: IXMLNode;
NodeList: IXMLNodeList;
begin
Result := '';
QryNode := FXMLDocument.DocumentElement;
// The following also work:
// '//Address/Name'
// '//Name'
NodeList := XPathSelect(QryNode, '//ShipTo/Address/Name');
if NodeList.Length > 0 then
QryNode := NodeList.Item[0]
else
QryNode := nil;
if Assigned(QryNode) then
Result := QryNode.FirstChild.Text; // Now has 'SOME COMPANY'
end;
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