getEventListeners is not defined in PuppeteerSharp

Question

When I try to use getEventListeners in puppeteerSharp I got getEventListeners is not defined error:

var result = await page.EvaluateExpressionHandleAsync("getEventListeners(document.forms[0].getElementsByTagName('button')[0])");

How to use getEventListeners within puppeteerSharp?

I found this for javascript:

const cdp = await page.target().createCDPSession();    
const listeners = await cdp.send('DOMDebugger.getEventListeners', { objectId });

and I tried to convert it back into C#:

var t = await page.EvaluateExpressionHandleAsync(@"document.forms[0].getElementsByTagName('button')[0]");
var client = await page.Target.CreateCDPSessionAsync();
var result = await client.SendAsync("DOMDebugger.getEventListeners", t.RemoteObject.ObjectId);

but it seems I'm doing something wrong and I did not find any clear documentation about this.

getEventListeners is a console utility that is not an available function to use in a script https://developers.google.com/web/tools/chrome-devtools/console/utilities#geteventlisteners — hardkoded, Feb 20 '21 at 16:44
@hardkoded here: https://stackoverflow.com/questions/63059096/chrome-devtools-protocol-how-to-get-click-event-handler-name-of-a-node in the first answer, it seems he uses `getEventListeners`. but I do not know how to convert it back into c# — Inside Man, Feb 21 '21 at 03:25

Inside Man · Accepted Answer · 2021-02-22T08:11:17.507

I have found the solution, here it is for those who may be interested:

First, we should create a CDPSession like this:

var client = await page.Target.CreateCDPSessionAsync();

then we should Evaluate our script to get an element:

var body = await client.SendAsync("Runtime.evaluate", new { expression = "document.getElementsByTagName('input')[0]" });

and at last, we should use DOMDebugger with the element's objectId to get its event listeners:

var result = await client.SendAsync("DOMDebugger.getEventListeners", new { objectId = body["result"]["objectId"] });

getEventListeners is not defined in PuppeteerSharp

1 Answers1