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Call a C# Method From JavaScript Hosted in a WebBrowser

, 6 May 2011 CPOL
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This demonstrates how you can call a C# method in a Windows Forms application from JavaScript that is hosted in a webpage inside a WebBrowser control on your form.
This sample demonstrates how to call C# from JavaScript. It also shows that parameters can be passed to C# methods.
 
First, create a Windows Forms application. Then, add a WebBrowser control to your form. Then modify the code for the form so it looks like this:
 
namespace WindowsFormsApplication6
{
    // This first namespace is required for the ComVisible attribute used on the ScriptManager class.
    using System.Runtime.InteropServices;
    using System.Windows.Forms;
 
    // This is your form.
    public partial class Form1 : Form
    {
        // This nested class must be ComVisible for the JavaScript to be able to call it.
        [ComVisible(true)]
        public class ScriptManager
        {
            // Variable to store the form of type Form1.
            private Form1 mForm;
 
            // Constructor.
            public ScriptManager(Form1 form)
            {
                // Save the form so it can be referenced later.
                mForm = form;
            }
 
            // This method can be called from JavaScript.
            public void MethodToCallFromScript()
            {
                // Call a method on the form.
                mForm.DoSomething();
            }
 
            // This method can also be called from JavaScript.
            public void AnotherMethod(string message)
            {
                MessageBox.Show(message);
            }
        }
 
        // This method will be called by the other method (MethodToCallFromScript) that gets called by JavaScript.
        public void DoSomething()
        {
            // Indicate success.
            MessageBox.Show("It worked!");
        }
 
        // Constructor.
        public Form1()
        {
            // Boilerplate code.
            InitializeComponent();
 
            // Set the WebBrowser to use an instance of the ScriptManager to handle method calls to C#.
            webBrowser1.ObjectForScripting = new ScriptManager(this);
 
            // Create the webpage.
            webBrowser1.DocumentText = @"<html>
                <head>
	                <title>Test</title>
                </head>
                <body>
	            <input type=""button"" value=""Go!"" onclick=""window.external.MethodToCallFromScript();"" />
                    <br />
                    <input type=""button"" value=""Go Again!"" onclick=""window.external.AnotherMethod('Hello');"" />
                </body>
                </html>";
        }
    }
}
Note that your application may be part of a namespace other than WindowsFormsApplication6, but the rest of the code should work if you follow the above instructions explicitly. I created this tip/trick because somebody asked me a question and they didn't understand this sample that I sent them to. This tip/trick makes the sample more understandable by fixing the two bugs I spotted, adding the using statements that weren't mentioned, and by heavily commenting the code. Hopefully the rest of you will find this of use as well.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

AspDotNetDev
Web Developer
United States United States
  • Managing Your JavaScript Library in ASP.NET (if you work with ASP.net and you don't read that, you are dead to me).
  • Graduated summa cum laude with a BS in Computer Science.
  • Wrote some articles and some tips.
  • DDR ("New high score? What does that mean? Did I break it?"), ping pong, and volleyball enthusiast.
  • Software I have donated to (you should too):

Comments and Discussions

 
GeneralMy vote of 5 PinmemberMember 36728947-May-14 23:24 
QuestionThank you PinmemberNargis Hemani8-Aug-13 11:37 
Questionhas you tried webkit or xullrunner Pinmemberpepelepeo12-Mar-12 13:38 
AnswerRe: has you tried webkit or xullrunner PinprotectorAspDotNetDev12-Mar-12 14:00 
GeneralRe: I updated the code so that webBrowser1.DocumentText is set r... PinprotectorAspDotNetDev6-May-11 5:15 
GeneralRe: I think that you need to call webBrowser1.Document.Write("..... PinmemberAnton Levshunov6-May-11 2:08 
GeneralI want to call C# methods using java script in a Mobile Appl... PinmemberAUDissa15-Feb-12 1:49 
GeneralRe: It's possible. Please see my message in the forum below: htt... PinprotectorAspDotNetDev15-Feb-12 8:34 
GeneralGood tip... PinmemberPrasanta_Prince6-May-11 8:03 
GeneralwebBrowser1 is Uninitialized,so throws a null pointer except... Pinmembergeaglem5-May-11 18:48 
GeneralRe: You are absolutely right, and thank you for the fix. I must ... PinprotectorAspDotNetDev5-May-11 19:01 
GeneralReason for my vote of 5 Interesting article. PinmemberÁngel Manuel García Carmona8-Dec-10 6:14 
GeneralWow! I didn't realize that this is even possible! Thx! Vote... Pinmembern.podbielski1-Dec-10 21:19 
GeneralI am explicilty using Form1 because the ONLY reason ScriptMa... Pinprotectoraspdotnetdev30-Nov-10 5:54 
GeneralReason for my vote of 4 Good tip. But why using explicitly F... Pinmembersjelen30-Nov-10 3:28 
GeneralReason for my vote of 5 nice tip. thanks! PinmemberWhiteRose161129-Nov-10 3:26 
GeneralReason for my vote of 5 Excellent! Great help for me! PinmemberJohnSmithPer24-Nov-10 14:12 
GeneralHow can i pass a JavaScript variable in C# using a button in... PinmemberJohnSmithPer24-Nov-10 13:31 
GeneralCode is working properly! Thanks for your help aspdotnetdev.... PinmemberJohnSmithPer24-Nov-10 12:49 
GeneralThanks for the heads up, but I'm sure this code is running p... Pinprotectoraspdotnetdev23-Nov-10 19:58 
GeneralThis code is not running properly....when it executing webBr... PinmemberPalash Biswas23-Nov-10 19:44 
GeneralRe: geaglem informed me of the problem, and I have implemented t... PinprotectorAspDotNetDev5-May-11 19:02 
SuggestionAUDissa (Regarding Calling C# From JavaScript on Windows Mobile) PinprotectorAspDotNetDev15-Feb-12 8:33 
GeneralRe: AUDissa (Regarding Calling C# From JavaScript on Windows Mobile) Pinmemberboogac29-Feb-12 12:12 
GeneralRe: AUDissa (Regarding Calling C# From JavaScript on Windows Mobile) PinprotectorAspDotNetDev29-Feb-12 16:16 

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