win新建html不显示,WinForms:设置ObjectForScripting时,不显示HTML

I have a Windows forms application and a separate HTML page. The two are supposed to communicate with each other. I followed the instructions from this microsoft link. Before I set the ObjectForScripting with WebBrowser.ObjectForScripting = this;, the HTML page displayed correctly. However, after setting ObjectForScripting, the HTML will not display in the WebBrowser component whatsoever. It gives the error "window.external is null or not an object."

C# code:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace FirstCSharpApp

{

[PermissionSet(SecurityAction.Demand, Name = "FullTrust")]

[System.Runtime.InteropServices.ComVisibleAttribute(true)]

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void Form1_Load(object sender, EventArgs e)

{

WebBrowser.AllowWebBrowserDrop = false;

WebBrowser.IsWebBrowserContextMenuEnabled = false;

WebBrowser.WebBrowserShortcutsEnabled = false;

WebBrowser.ObjectForScripting = this;

string curDir = Directory.GetCurrentDirectory();

WebBrowser.Navigate(new Uri(String.Format("file:///{0}/Timeline.html", curDir)));

}

private void GoButton_Click(object sender, EventArgs e)

{

// Works!

WebBrowser.Document.InvokeScript("test",

new String[] { "called from client code" });

}

private void homeToolStripMenuItem_Click(object sender, EventArgs e)

{

WebBrowser.GoHome();

}

private void goBackToolStripMenuItem_Click(object sender, EventArgs e)

{

WebBrowser.GoBack();

}

private void goForwardToolStripMenuItem_Click(object sender, EventArgs e)

{

WebBrowser.GoForward();

}

public void Test(String message)

{

// Does not work, or apparently even exist

MessageBox.Show(message, "client code");

}

}

}

HTML:

function test(message) {

alert(message);

}

Call client code.

Talk1:

You really should include YOUR code, just in case there was a copy paste mistake. It is one of the most common errors.

Solutions1

It looks like you are missing these attributes on your form class.

[PermissionSet(SecurityAction.Demand, Name="FullTrust")]

[System.Runtime.InteropServices.ComVisibleAttribute(true)]

You can set this property to any COM-visible object for which you want

its public properties and methods available to scripting code. You can

make a class COM-visible by marking it with the ComVisibleAttribute.

Talk1:

From my understanding on the docs, if it is public it will already be tagged as Com Visible. I tagged it anyway, and it did not fix my problem.