A very easy .NET “Applet”

Welliton Alves Toledo

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13 Mar 2005CPOL2 min read

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Make a Windows Forms UserControl work like an Applet.

Download demo project - 9.08 Kb

Introduction

Some time ago, I needed my web application to interact with a specific hardware in the computer, but I didn't want to write an ActiveX, I wanted to write it in a .NET language. So I made a search in the web and I found some examples that helped me on that. In this article I will use a UserControl as an applet on my .htm page.

This example of "applet" doesn't make anything relevant. It's only to show how to put a Windows Form's code in a web page and interact with its properties and methods.

How it works?

Everything is very simple, it isn’t a “black box”. I created a Class Library project, then I added a Windows Forms UserControl and drag-and-drop'ed some components. Then I added an HTML page in the same project and I changed the code to:

HTML

<html>
   <head>
   <title>My Applet</title>
   <script language=javascript>
   <!--

     function Button1_onclick() {
        document.getElementById("myID").MyMethodReset();
    }

   //-->
  </script>
  </head>
  <body>
      <OBJECT id="myID" height="150" width="300" 
        classid="http:bin/release/CSharpApplet.dll#CSharpApplet.MyApplet"
        VIEWASTEXT>
     </OBJECT>
    <P>
    <INPUT id="Button1" type="button" value="Reset by way of javascript" 
        name="Reset" onclick="return Button1_onclick()">
  </body>
</html>

On the tag OBJECT the property classid is composed by the path (I used relative path) and name of the DLL, plus namespace and class name.

Note that MyApplet (UserControl) has a button with the caption “Reset” that calls the MyMethodReset public method, setting the value of the progress bar to zero. And on the HTML file, I have another button that calls the same public method MyMethodReset by way of JavaScript!

Remarks

You must create a WebSharing at the folder CSharpApplet from this source code example. Then run by, for example: http://localhost/CSharpApplet/MyApplet.htm.

Of course, .NET Framework is to be installed on clients.

Depending of what your user control will do and where it will run (by intranet/Internet), it will be necessary to trust the assembly by making proper settings on Administrative Tools > Microsoft .NET Framework Configuration/Wizards.

That’s all and sorry for my bad English!

Revision history

20 February 2005
English improvements :P

License

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

Written By

Welliton Alves Toledo

Web Developer

Brazil

Welliton is a nice brazilian guy.
He started the kidding with software with his "top" PC-AT 286 in 1991 when he was 14 years old.
Now he begins solo career in a software company (http://www.actuar.com.br) in Goiânia-Goiás - Brazil

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