设置IHTMLInputTextElement的值时为什么会出现访问冲突？ [英] Why do I get an access violation when setting the value of an IHTMLInputTextElement?

问题描述

我收到以下错误：

模块 project1.exe中地址0050AA07的访问冲突。读取的地址为00000000。

Access Violation at address 0050AA07 in module "project1.exe". Read of address 00000000.

我试图在TWebBrowser中自动填写表格。这只是表单上称为登录的字段。

I'm trying to auto fill a form in TWebBrowser. It's just a field called 'login' on a form.

这是什么意思？我该如何解决？

What does it mean? How do I solve it?

procedure TForm1.Button2Click(Sender: TObject);
var
  doc: IHTMLDocument2;
  frm: IHTMLFormElement;
  fld: IHTMLInputTextElement;
begin
  doc := webbrowser1.Document as IHTMLDocument2;
  frm := doc.forms.item(0, EmptyParam) as IHTMLFormElement;
  fld := frm.item('login', EmptyParam) as IHTMLInputTextElement;
  fld.value := 'someone';
end;

推荐答案

这意味着您正在取消引用设置为 nil 和尝试执行此非法行为的代码位于您的进程中的 $ 0050AA07 。

It means you are dereferencing a pointer that is set to nil and the code that is attempting this illegal act is located at $0050AA07 in your process.

如果您不能从中解决问题，那么如果向我们展示代码，我们可以告诉您为什么将指针设置为 nil

If you can't solve it from this, then if showed us the code we could tell you why your pointer is set to nil.

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