Xamarin.iOS WebView disappears after 10th reload - xamarin

Question

I got a basic WebView in Xamarin.Forms like this:
<WebView AbsoluteLayout.LayoutBounds="0, 0, 1, 1" AbsoluteLayout.LayoutFlags="All" x:Name="ChartWebView" Style="{StaticResource BackgroundStyle}">
<WebView.Source>
<HtmlWebViewSource Html="{Binding ChartHTML}" />
</WebView.Source>
</WebView>
I use the WebView to display a Chart.js diagram which works perfectly fine. On my page i got a button where the user can request data.
private async Task RequestData()
{
//Doing some stuff to get data ...
BuildChartHTML();
}
private void BuildChartHTML()
{
var html = GetChartJSConfigString();
Device.BeginInvokeOnMainThread(() =>
{
ChartWebView.Source = new HtmlWebViewSource
{
Html = html
};
});
}
However, on iOS only, everytime on exactly the 10th request/reload the WebView gets blank. It also stays blank after that. I need to re-navigate to this page to get it up and running again. I tried adjusting the height on WebView.Navigated as described in this thread, without success.
The problem doesn't accure on Android with the same code base.
Open to any workarounds if this is a framework bug.
PS: I obviously made sure that the html I'm loading is not broken. I loaded the same data 10 times and i compared the html loaded on the 10th time where the WebView broke. It was exactly the same HTML string.

Answer 1

Turned out to be a problem with iOS WKWebView and the use of HTML canvas (chart.js is renderered on a canvas).
After debugging into my WebView (stupid me not thinking about that possiblity before), i found out that the canvas memory exceeded the limit. With the help of a solution posted here i managed to avoid this problem.
Keep in mind this solution is a little bit hacky. Basically what I've done is, as pointed out in the link above, i "deleted" the canvas everytime i reload my chart. By "deleting" i mean setting the canvas to width and height to zero. Applied to my code the solution looks like this:
Inside my javascript that runs in the browser i added a function like this:
function deleteCanvas() {
//Get the main canvas where the chart is rendered to
var chart = document.getElementById('chart');
chart.height = 0;
chart.width = 0;
}
And then everytime i call my BuildChartHTML() function i call this method in my c# code like this:
Device.BeginInvokeOnMainThread(() =>
{
ChartWebView.Source = new HtmlWebViewSource
{
Html = html
};
ChartWebView.Eval("deleteCanvas()");
});