Windows Application interaction with a Web Page
Displaying a web page inside a widows form application and interact with the content it’s very simple using System.Windows.Forms.WebBrowser.
This way you can easily create a panel containing ads in to your application or even communicate with a 3rd Party web component for displaying data. In our case we needed to integrate an enterprise application with an applet provided by Oracle that was capable of displaying and comparing 3d models.
First step in order to archive this goal is adding a WebBrowser control in one of your forms, or better inside a UserControl to allow a better code separation and reuse.
In order to load a web page in the WebBrowser control you must set the “Url” property of this control. If you run your application you will see that the page is loaded inside the panel of the control.
Interaction with the WebPage is also very simple. If you need to call methods inside your application from the web page you just loaded you just need to set the “ObjectForScripting” property of the WebBrowser control to the object that must handle the requests from the page. By example if want to send text messages from javascript and make use of them inside your web application the code would look like bellow.
C#
1 2 3 4 5 6 | webBrowserContainer.ObjectForScripting = this; … public void sendMessage(string text) { MessageBox.Show(text); } |
JavaScript
1 2 3 4 | function buttonClick() { window.external.sendMessage('Button was clicked!!!'); } |
Setting the “ObjectForScripting” will set the container of the WebBrowser control as the target for JavaScript calls. Calling of the method is very simple from JavaScript with “window.external”.
Calling JavaScript function is also very simple like presented in the code sample bellow.
C#
1 2 3 4 | public void jsCall() { var result = webBrowserContainer.Document.InvokeScript("showText", new object[1] { "Windows Application Call" }); } |
JavaScript
1 2 3 4 5 6 7 8 | function showText(text) { alert(text); var results = new Array(); results[0] = “Value1”; results[2] = “Value2”; } |
As you can see simple calls can be made very easily and parameters can be sent through an object array. If the JavaScript function returns a more complex result like an Array or even a custom type constructed by the developer, this can be processed in C# with the help of reflection. The “jsCall” code will change like bellow.
C#
1 2 3 4 5 6 7 8 9 10 | public void jsCall() { var result = webBrowserContainer.Document.InvokeScript("showText", new object[1] { "Windows Application Call" }); if (result != null) { Type jsType = result.GetType(); string content = (string) jsType.InvokeMember( “toString”, System.Reflection.BindingFlags.Default | System.Reflection.BindingFlags.InvokeMethod, null, result, null); string[] values = content.Split(“,”); } } |
Other properties like “length”, in this case, can also be interrogated from the result object.
As you can see the WebBrowser control can be a very useful and easy to use tool in building windows application that need to show web content or even interact with more complex functionalities.
Tags: .NET C# javascript System.Windows.Forms.WebBrowser
Posted in: Microsoft.NET
May 19, 2010
| 
Florin Stoian | 
3 Comments
3 Responses
July 1, 2010 1
this post is very usefull thx!
July 2, 2010 2
Great, I never knew this, thanks.
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