为什么在设置 IHTMLInputTextElement 的值时会出现访问冲突? [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.读取地址 00000000.

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

我正在尝试在 TWebBrowser 中自动填写表单.它只是表单上一个名为登录"的字段.

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

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一个设置为 nil 的指针，并且尝试这种非法行为的代码位于 $0050AA07 在您的过程中.

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.

如果你不能从这里解决它，那么如果向我们展示代码，我们可以告诉你为什么你的指针被设置为 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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