尝试编辑 IHTMLDocument 会挂起应用程序

Question

基于 IHTMLDocument2 的 MSHTML 文档，我正在尝试编写简单的 HTML 解析器。 不幸的是，尝试设置编辑模式失败，换句话说，resultState 永远不会获得“完整”值，因此应用程序挂起。

{$APPTYPE CONSOLE}

function ParseHtml(doc: TStringList): TStringList;
var
  iHtml: IHTMLDocument2;
  v: Variant;
  msg: tagMSG;
begin
  iHtml := CreateComObject(CLASS_HTMLDocument) as IHTMLDocument2;
  Result := TStringList.Create;
  try
    try
      iHtml.designMode := 'on';
      while iHtml.readyState <> 'complete' do
        PeekMessage(msg, 0, 0, 0, PM_NOREMOVE);
//    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
//    above loop never finishes  
      v := VarArrayCreate([0, 0], varVariant);
      v[0] := doc.Text;
      iHtml.write( PSafeArray(TVarData(v).VArray) );
      iHtml.designMode := 'off';
      while iHtml.readyState <> 'complete' do
        PeekMessage(msg, 0, 0, 0, PM_NOREMOVE);
      // processing iHtml.body
      ...
    except
      ...
    end;
  finally
    ...
  end;
  ...
end;

begin
  CoInitialize(nil);
  ...
  CoUninitialize;  
end.

只是好奇为什么 IHTMLDocument2 接口的readyState 属性从未设置为“完整”，尽管基于官方文档它应该如此？

Answer 1

readyState 属性未设置为 'complete'，因为您尚未告知 IHTMLDocument2 对象实际加载文档。您必须加载一个文档，即使是空白文档（即：'about:blank' URL），才能影响 readyState 属性，否则它将保持其状态'uninitialized' 的初始值。

Answer 2

无需将 designMode 设置为 on。也不需要轮询readyState。一旦您写入并关闭文档，它就会被设置为“完成”：

program Test;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  MSHTML,
  ActiveX,
  ComObj;

procedure DocumentFromString(Document: IHTMLDocument2; const S: WideString);
var
  v: OleVariant;
begin
  v := VarArrayCreate([0, 0], varVariant);
  v[0] := S;
  Document.Write(PSafeArray(TVarData(v).VArray));
  Document.Close;
end;

var
  Document: IHTMLDocument2;
  Elements: IHTMLElementCollection;
  Element: IHTMLElement;
begin
  CoInitialize(nil);

  Document := CreateComObject(CLASS_HTMLDocument) as IHTMLDocument2;
  DocumentFromString(Document, '<b>Hello</b>');
  Writeln(string(Document.readyState));

  // process the Document here
  Elements := Document.all.tags('b') as IHTMLElementCollection;
  Element := Elements.item(0, '') as IHTMLElement;
  Writeln(string(Element.innerText));
  Readln;

  CoUninitialize;
end.