Possibly a bug in HtmlElement.GetAttribute()

venky

I found that calling the HtmlElement.GetAttribute() method results in an JavaScriptException - ReferenceError when trying to read the custom html attribute data-*

For example, when you have DIV with custom attribute data-text, the error is:

JavaScriptException - ReferenceError: text is not defined
Source=LINQPad.GUI

 -LINQPad.UI.OutputWebBrowser2+<RunScriptAsync>d__48 Void MoveNext() offset: 0x1B4
 -System.Runtime.ExceptionServices.ExceptionDispatchInfo Void Throw() offset: 0x11
 -System.Runtime.CompilerServices.TaskAwaiter Void HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task, System.Threading.Tasks.ConfigureAwaitOptions) offset: 0x2D
 -System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter TResult GetResult() offset: 0x0
 -LINQPad.UI.ResultsWebBrowser2+<>c__DisplayClass23_0+<<OnHtmlActionRequested>g__GoBSync|0>d Void MoveNext() offset: 0xC25
 -System.Runtime.ExceptionServices.ExceptionDispatchInfo Void Throw() offset: 0x11
 -System.Runtime.ExceptionServices.ExceptionDispatchInfo Void Throw(System.Exception) offset: 0x0
...

Example code to reproduce:

<Query Kind="Statements">
  <Namespace>LINQPad.Controls</Namespace>
</Query>

EventHandler<PropertyEventArgs> ehObjClick = new EventHandler<PropertyEventArgs>(HandleObjClick);

Div d = new Div();
d.HtmlElement.InnerText="Click me..";
d.Styles["width"] = "5em";
d.Styles["height"] = "5em";
d.Styles["border"] = "1px black solid";

d.HtmlElement.SetAttribute("data-text", "text1");

d.Click += (o, e) => ehObjClick(o, new PropertyEventArgs());

d.Dump();

void HandleObjClick(object sender, PropertyEventArgs args)
{
    var elem = sender as LINQPad.Controls.Core.HtmlElement;
    if (elem != null)
    {
        XElement.Parse(elem.ToString()).Dump();

        string dataText = (string)elem.InvokeScript(true, "eval", $"targetElement.getAttribute('data-text')");
        $"OK: data-text: {dataText}".Dump("Get Attribute using InvokeScript (targetElement.getAttribute()):");

        string err = string.Empty;
        try
        {               
            dataText = elem.GetAttribute("data-text");      
        }
        catch (Exception ex)
        {
            err = ex.Message;
        }
        err.Dump("Get Attribute using HtmlElement.GetAttribute():");
    }
}

JoeAlbahari

Thanks - will fix this in the next build.

Note that you can also work around it by fetching the attribute as follows:

elem.GetAttribute("dataset.text")

venky

I hadn't thought of that, thanks..