Invoking JavaScript function from WinForms

Submitted by emond on Saturday, September 24, 2011 - 00:43.

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I've been working on application that needs to load page and display it in WebBrowser control. Requirement was to allow interaction between WinForms application and web page. Here I will show a sample application where JavaScript function is called from WinForms application. For this Blog I will be using Google Web elements , Google Web Elements allow you to easily add your favorite Google products to your website. http://www.google.com/webelements/#!/custom-search Process can be described by following steps: Create Windows Forms application Drop WebBrowser control into Form Create Html with JavaScript function you want to call Calling JavaScript function from WinForms application isn't so difficult. .NET WebBrowser control has property Document which gets an HtmlDocument representing the Web page currently displayed in the WebBrowser control. Well this javascript part is not well written ,maybe my Web God-Like Buddy (Rustan) can clean this mess..lol anyway here's the script JAVASCRIPT

 <script type="text/javascript">
 
    google.load("elements", "1", {packages: "keyboard"});
    
    var kbd;
    
    function onLoad() {
      var content = document.getElementById('content');
      // Create the HTML for out text area
      content.innerHTML = '<div>' +
                          'Demo of Invoking JavaScript using .NET' +
                          '.</div>' +
                          '<textarea id="t1" cols="47" rows="7"></textarea>';
    
      kbd = new google.elements.keyboard.Keyboard(
          [google.elements.keyboard.LayoutCode.ENGLISH],
          ['t1']);
    }
 
    function ChangeLayout() {
    
    var LayOut=document.getElementById('txtLang').value;
      kbd.setLayout(LayOut);   
         
   }
       
  
    function toggleVisible() {
   
      if (kbd.isVisible()) {
        kbd.setVisible(false);
      } else {
        kbd.setVisible(true);
  
      }
    }
    
   
    google.setOnLoadCallback(onLoad);
    
    </script>

So how can you call JavaScript functions in your WebBrowser control? Call the InvokeScript method on the HtmlDocument. .NET CODE (winforms)

 Sub SHOW_HIDE_VIR_KEYBOARD()
        With Me.WBrowser
 
            .Document.InvokeScript("toggleVisible", New Object() {""})  'call the javascript from the .htm files
 
        End With
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdShow.Click
        SHOW_HIDE_VIR_KEYBOARD()
    End Sub
 
   
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        With Me.WBrowser
            .Document.GetElementById("txtLang").InnerText = Trim(Me.ComboBox1.Text)  'parse data from winforms to Htm files
            .Document.InvokeScript("ChangeLayout", New Object() {""})  'call the javascript from the .htm files
 
        End With
    End Sub
 
 

Conclusions: With the ability to call JavaScript from .NET App you can now embed and extend web applications into native applications with ease. A native application gives you more control over the environment and access to computer resources that you cannot access from a web page. You can Mashup web applications with computer hardware or software in new and interesting ways. For the complete sample please download the demo project For questions just Contact me @ the Addresses below: mobile : +639399393702

http://www.emondsoft-solutions.com/

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