Command webbrowser

15y3.6kVisual Basic .NET

I can not fix the error anyone can help me? ..

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace test
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{

webBrowser1.Navigate(" http://www.httpsurf.com/ ");

//the debugger tells me that the error in this line
webBrowser1.Document.GetElementById("url").InnerText = textBox1.Text;

webBrowser1.Document.GetElementById("go").InvokeMember("Click");

}

private void textBox1_TextChanged(object sender, EventArgs e)
{

}
}
}

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sam Hobbs15y ago
First, please don't use such a large font; it makes it diffcult to see all the code.

Second, please see my article Introduction to Web Site Scraping.
Javeed M Shaikh15y ago
try this...

webBrowser1.Navigate(" http://www.httpsurf.com/ ");

webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);

// here is the event
void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
webBrowser1.Document.GetElementById("Url").InnerText = textBox1.Text;
}
15y ago
I tried that code but it does not work..
Jean Paul15y ago
The error was occurring because the code was accessing Document object which was not created yet (as navigation in progress).

Following is the corrected code.

webBrowser1.Navigate(" http://www.httpsurf.com/ ");

webBrowser1.Navigated += (object sender2, WebBrowserNavigatedEventArgs e2) =>
{
//the debugger tells me that the error in this line
webBrowser1.Document.GetElementById("url").InnerText = textBox1.Text;

//webBrowser1.Document.GetElementById("go").InvokeMember("Click");
};

Please note that you have to ensure the event is not called multiple times (delegate, invoking click)
Vulpes15y ago
You haven't said what the error is but, if there isn't an HTMLElement with an ID of "url", this expression will be null:

webBrowser1.Document.GetElementById("url")

and the line you specified will then give an 'object not set to an instance of an object' exception.

To prevent the exception, you'd therefore need to do this:

if (webBrowser1.Document.GetElementById("url") != null)
{
webBrowser1.Document.GetElementById("url").InnerText = textBox1.Text;
}