Breaking News

Wednesday, April 28, 2010

WebBrowser Control: Callbacks not working!

Problem statement:
Callbacks not working in WebBrowser control.

Possible resolution:
Check to see if your code is COM Callable? Because for WebBroswer.ObjectForScripting to work COMVisible attribute must be added and set to true.


Something like following on the top of the class declaration:

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

From MSDN:

Use this property to enable communication between a Web page hosted by the WebBrowser control and the application that contains the WebBrowser control. This property lets you integrate dynamic HTML (DHTML) code with your client application code. The object specified for this property is available to Web page script as the window.external object, which is a built-in DOM object provided for host access.

From MSDN:

using System;
using System.Windows.Forms;
using System.Security.Permissions;

[PermissionSet(SecurityAction.Demand, Name="FullTrust")]
[System.Runtime.InteropServices.ComVisibleAttribute(true)]
public class Form1 : Form
{
    private WebBrowser webBrowser1 = new WebBrowser();
    private Button button1 = new Button();

    [STAThread]
    public static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new Form1());
    }

    public Form1()
    {
        button1.Text = "call script code from client code";
        button1.Dock = DockStyle.Top;
        button1.Click += new EventHandler(button1_Click);
        webBrowser1.Dock = DockStyle.Fill;
        Controls.Add(webBrowser1);
        Controls.Add(button1);
        Load += new EventHandler(Form1_Load);
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        webBrowser1.AllowWebBrowserDrop = false;
        webBrowser1.IsWebBrowserContextMenuEnabled = false;
        webBrowser1.WebBrowserShortcutsEnabled = false;
        webBrowser1.ObjectForScripting = this;
        // Uncomment the following line when you are finished debugging.
        //webBrowser1.ScriptErrorsSuppressed = true;

        webBrowser1.DocumentText =
            "" +
            "";
    }

    public void Test(String message)
    {
        MessageBox.Show(message, "client code");
    }

    private void button1_Click(object sender, EventArgs e)
    {
        webBrowser1.Document.InvokeScript("test",
            new String[] { "called from client code" });
    }
}

Happy 'callback'ing! (0:

1 comment:

  1. It was really a nice article and i was really impressed by reading this article
    postdated cheque management | check writing software

    ReplyDelete

Designed By Published.. Blogger Templates