delphi读取xml元素 [英] delphi read xml element

问题描述

我是XML的新手，我们需要使用新的 Bing空间数据API 。我设法以xml格式从他们那里得到一个结果。我如何读取响应中的特定元素，即。链接，状态和错误消息？

I'm new to XML and we need to do GeoCoding with the new Bing Spatial Data API. I've managed to get a result back from them in xml format. How would I read specific elements in the response, ie. the Link, Status and ErrorMessages?

<?xml version="1.0" encoding="utf-8"?>
<Response xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.microsoft.com/search/local/ws/rest/v1">
    <Copyright>Copyright © 2011 Microsoft and its suppliers. All rights reserved. This API cannot be accessed and the content and any results may not be used, reproduced or transmitted in any manner without express written permission from Microsoft Corporation.</Copyright>
    <BrandLogoUri>http://spatial.virtualearth.net/Branding/logo_powered_by.png</BrandLogoUri>
    <StatusCode>201</StatusCode>
    <StatusDescription>Created</StatusDescription>
    <AuthenticationResultCode>ValidCredentials</AuthenticationResultCode>
    <TraceId>ID|02.00.82.2300|</TraceId>
    <ResourceSets>
        <ResourceSet>
            <EstimatedTotal>1</EstimatedTotal>
            <Resources>
                <DataflowJob>
                    <Id>ID</Id>
                    <Link role="self">https://spatial.virtualearth.net/REST/v1/dataflows/Geocode/ID</Link>
                    <Status>Pending</Status>
                    <CreatedDate>2011-03-30T08:03:09.3551157-07:00</CreatedDate>
                    <CompletedDate xsi:nil="true" />
                    <TotalEntityCount>0</TotalEntityCount>
                    <ProcessedEntityCount>0</ProcessedEntityCount>
                    <FailedEntityCount>0</FailedEntityCount>
                </DataflowJob>
            </Resources>
        </ResourceSet>
    </ResourceSets>
</Response>

我使用的是Delphi XE。

I'm using Delphi XE.

请问，Pieter

推荐答案

如何使用一些简单的XPATH来获取请求的值？

How about using some simple XPATH to get the requested values?

// Link [1] / node（） - 从整个文档中选择第一个链接节点，然后选择第一个子节点任何一种。只是发生第一个子节点是包含实际 https 链接的未命名节点。

//Link[1]/node() - selects the first "Link" node from the whole document, and then selects the first child node of any kind. It just happens that the first child node is the unnamed node containing the actual https link.

假设XML文档加载到 Doc：TXMLDocument 中，您可以使用以下代码解压缩链接：

Assuming the XML document is loaded into Doc: TXMLDocument, you can extract the Link with this code:

(Doc.DOMDocument as IDomNodeSelect).selectNode('//Link[1]/node()').nodeValue

您可以找到有关XPath的一些文档阅读这些XPath示例MSDN 。您可以在w3schools找到更好的文档。而最重要的是，这是一个简单（但完整的）控制台应用程序，它使用XPath来提取和显示3个请求的值：

You can find some documentation about XPath reading those XPath Examples on MSDN. You might find better documentation at w3schools. And to top it all up, here's a simple (but complete) console application that uses XPath to extract and display the 3 requested values:

program Project14;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  Xmldoc,
  xmldom,
  ActiveX;

var X: TXMLDocument;
    Node: IDOMNode;
    Sel: IDomNodeSelect;

begin
  try
    CoInitialize(nil);

    X := TXMLDocument.Create(nil);
    try

      // Load XML from a string constant so I can include the exact XML sample from this
      // question into the code. Note the "SomeNode" node, it's required to make that XML
      // valid.

      X.LoadFromXML(
        '<SomeNode>'+
        '  <Link role="self">' +
        '    https://spatial.virtualearth.net/REST/v1/dataflows/Geocode/jobid' +
        '  </Link>' +
        '  <Status>Aborted</Status>' +
        '  <ErrorMessage>The data uploaded in this request was not valid.</ErrorMessage>' +
        '</SomeNode>'
      );

      // Shortcut: Keep a reference to the IDomNodeSelect interface

      Sel := X.DOMDocument as IDomNodeSelect;

      // Extract and WriteLn() the values. Painfully simple!

      WriteLn(Sel.selectNode('//Link[1]/node()').nodeValue);
      WriteLn(Sel.selectNode('//Status[1]/node()').nodeValue);
      WriteLn(Sel.selectNode('//ErrorMessage[1]/node()').nodeValue);

      ReadLn;
    finally X.Free;
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

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