WebBrowser.Navigating Event
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Occurs before the WebBrowser control navigates to a new document.
public:
event System::Windows::Forms::WebBrowserNavigatingEventHandler ^ Navigating;public event System.Windows.Forms.WebBrowserNavigatingEventHandler Navigating;public event System.Windows.Forms.WebBrowserNavigatingEventHandler? Navigating;member this.Navigating : System.Windows.Forms.WebBrowserNavigatingEventHandler Public Custom Event Navigating As WebBrowserNavigatingEventHandler Public Event Navigating As WebBrowserNavigatingEventHandler Event Type
Examples
The following code example demonstrates how to use a handler for the Navigating event to cancel navigation when a Web page form has not been filled in. The Document property is used to determine whether the form input field contains a value.
This example requires that your form contains a WebBrowser control called webBrowser1 and that your form class has a ComVisibleAttribute making it accessible to COM.
For a complete code example that you can paste the following code into, see How to: Add Web Browser Capabilities to a Windows Forms Application.
private void Form1_Load(object sender, EventArgs e)
{
webBrowser1.DocumentText =
"<html><body>Please enter your name:<br/>" +
"<input type='text' name='userName'/><br/>" +
"<a href='http://www.microsoft.com'>continue</a>" +
"</body></html>";
webBrowser1.Navigating +=
new WebBrowserNavigatingEventHandler(webBrowser1_Navigating);
}
private void webBrowser1_Navigating(object sender,
WebBrowserNavigatingEventArgs e)
{
System.Windows.Forms.HtmlDocument document =
this.webBrowser1.Document;
if (document != null && document.All["userName"] != null &&
String.IsNullOrEmpty(
document.All["userName"].GetAttribute("value")))
{
e.Cancel = true;
System.Windows.Forms.MessageBox.Show(
"You must enter your name before you can navigate to " +
e.Url.ToString());
}
}
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
Handles Me.Load
webBrowser1.DocumentText = _
"<html><body>Please enter your name:<br/>" & _
"<input type='text' name='userName'/><br/>" & _
"<a href='http://www.microsoft.com'>continue</a>" & _
"</body></html>"
End Sub
Private Sub webBrowser1_Navigating( _
ByVal sender As Object, ByVal e As WebBrowserNavigatingEventArgs) _
Handles webBrowser1.Navigating
Dim document As System.Windows.Forms.HtmlDocument = _
webBrowser1.Document
If document IsNot Nothing And _
document.All("userName") IsNot Nothing And _
String.IsNullOrEmpty( _
document.All("userName").GetAttribute("value")) Then
e.Cancel = True
MsgBox("You must enter your name before you can navigate to " & _
e.Url.ToString())
End If
End Sub
Remarks
The WebBrowser control navigates to a new document whenever one of the following properties is set or methods is called:
You can handle the Navigating event to cancel navigation if certain conditions have not been met, for example, when the user has not completely filled out a form. To cancel navigation, set the Cancel property of the WebBrowserNavigatingEventArgs object passed to the event handler to true. You can also use this object to retrieve the URL of the new document through the WebBrowserNavigatingEventArgs.Url property. If the new document will be displayed in a Web page frame, you can retrieve the name of the frame through the WebBrowserNavigatingEventArgs.TargetFrameName property.
Handle the Navigated event to receive notification when the WebBrowser control finishes navigation and has begun loading the document at the new location. Handle the DocumentCompleted event to receive notification when the WebBrowser control finishes loading the new document.
For more information about handling events, see Handling and Raising Events.
