First you need to create a Windows Forms application using Visual Studio and on the Form, add a TextBox and a Button control. Also, double click on the button control to wirte its click event handler.

You also need to import two namespacces by adding "using SHDocVw;" and "using System.Runtime.InteropServices;" to the top of your code.

You will probably need to add the Microsoft Internet Controls reference as well.

WebBrowserApp webBrowser = null;
InternetExplorer explorer = new InternetExplorerClass();
ShellWindows shWin = new ShellWindows();

public Form1()
{
InitializeComponent();
webBrowser = (IWebBrowserApp)explorer;
}

private void button1_Click(object sender, EventArgs e)
{
//open browser to url typed into text box
IEOpenOnURL(textBox1.Text);
}

public void IEOpenOnURL(string url)
{
object o = null;
bool b = false;

//check if window is already open
foreach (InternetExplorer ies in shWin)
{

if (ies.HWND == webBrowser.HWND)
b = true;
}

try
{

if (b)
{
webBrowser .Visible = true;
webBrowser .Navigate(url, ref o, ref o, ref o, ref o);
}
else
{
//its not open so create new instance
explorer = new InternetExplorerClass();
webBrowser = (IWebBrowserApp)explorer;
webBrowser .Visible = true;
webBrowser .Navigate(url, ref o, ref o, ref o, ref o);
}
}
catch (Exception)
{ // implement your exception handling here
}
}