我在运行时创建 TXMLDocument 的实例,以加载和解析 XML 文件。您可以检查以下代码:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, xmldom, XMLIntf, msxmldom, XMLDoc, StdCtrls;
type
Txml = class(TForm)
// XMLDocument1: TXMLDocument;
Memo1: TMemo;
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
xml: Txml;
implementation
{$R *.dfm}
procedure Txml.FormCreate(Sender: TObject);
var i,j:integer;
aNode:IXMLNode;
ws:String;
XMLDocument1:TXMLDocument;
begin
Memo1.Lines.Clear;
XMLDocument1 := TXMLDocument.Create(nil);
try
XMLDocument1.LoadFromFile('C:\a.xml');
XMLDocument1.Active := true;
aNode := XMLDocument1.ChildNodes.First;
while aNode<>nil do
begin
for i := 0 to aNode.ChildNodes.Count-1 do
begin
if aNode.ChildNodes[i].NodeName = 'Role' then
begin
Memo1.Lines.Add('Tag - '+aNode.ChildNodes[i].ChildNodes['Tag'].Text);
for j := 0 to aNode.ChildNodes[i].ChildNodes.Count-1 do
if aNode.ChildNodes[i].ChildNodes[j].HasChildNodes then
begin
ws := VarToStr(aNode.ChildNodes[i].ChildNodes[j].ChildValues['Tag']);
if trim(ws)<>'' then
Memo1.Lines.Add(ws);
ws := VarToStr(aNode.ChildNodes[i].ChildNodes[j].ChildValues['Value']);
if trim(ws)<>'' then
Memo1.Lines.Add(ws);
end;
end;
end;
aNode := aNode.NextSibling;
end;
XMLDocument1.Active := false;
finally
FreeAndNil(XMLDocument1);
end;
end;
end.
问题是这正在生成一个 AV。正如您可能已经看到的那样,在组件出现在表单上之前 (// XMLDocument1: TXMLDocument;)。
为什么当组件在代码工作的表单上时,但是当我在运行时创建它时它会生成 AV?
LE: 解决方案:基于答案/评论和 Delphi 帮助:
XMLDocument1 : IXMLDocument; //not TXMLDocument
XMLDocument1 := LoadXMLDocument(...);
FreeAndNil;// must be deleted