Friday, 31 January 2014

Disable WebView scrolling in Windows Store Apps

WebView is a control which enables developers to host the HTML content. In WinRT framework WebView still lacks some features when we compare it to the WebBrowser of WPF. WebView class inherits from FrameworkElement class, but many properties of base class in not working in WebView.

Recently I was creating an app and I want to disable the horizontal & vertical scrolling of WebView. I tried below given code.

<WebView x:Name="webView" Source="http://myawesomewebsite.com"
    ScrollViewer.VerticalScrollBarVisibility="Disabled"
    ScrollViewer.VerticalScrollMode="Disabled"/>

But it didn't work. I was getting annoyed. I start binging & googling but didn't get any solution. WebView doesn't have its template also. Then I start analyzing the control in microscopic way. Finally I get to know that the scroll bars are due to HTML content, WebView itself doesn't have its own scroll bars. So I decided to go for JavaScript way. I applied some CSS properties in HTML content using JavaScript. It will display only that HTML content which is being displayed in current viewport or say display area. WebView provides InvokeScript method, which executes the specified script function from the currently loaded HTML, with specific arguments. When WebView's LoadCompleted event occurs, I am invoking that JavaScript which disables the scrolling. Check out whole code given below.

string DisableScrollingJs = @"function RemoveScrolling()
                              {
                                  var styleElement = document.createElement('style');
                                  var styleText = 'body, html { overflow: hidden; }'
                                  var headElements = document.getElementsByTagName('head');
                                  styleElement.type = 'text/css';
                                  if (headElements.length == 1)
                                  {
                                      headElements[0].appendChild(styleElement);
                                  }
                                  else if (document.head)
                                  {
                                      document.head.appendChild(styleElement);
                                  }
                                  if (styleElement.styleSheet)
                                  {
                                      styleElement.styleSheet.cssText = styleText;
                                  }
                              }";

void webView_LoadCompleted(object sender, NavigationEventArgs e)
{
    webView.InvokeScript("eval", new[] { DisableScrollingJs });
}

I hope this blog post will help you while developing WebView oriented app if you required such feature to implement.
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