CefSharp - Invalid (?) data returned from the C# method to JS

Question

I have a problem with the data returned from C # to JS. CefSharp configuration:

        Cef.Initialize();
        CefSharpSettings.WcfEnabled = true;
        CefSharpSettings.LegacyJavascriptBindingEnabled = true;
        browser = new ChromiumWebBrowser("")
        {
            Dock = DockStyle.Fill
        };
        this.Controls.Add(browser);
        SM = new ScriptManager(browser);
        browser.RegisterAsyncJsObject("external", SM); //"Support" for C# methods from JavaScript

I am trying to call the C# method from JS:

...
var UserID_array = window.external.loadUsrIDs(usr_names); //usr_name -> array of user names

In C# the declaration of method is as follows:

class ScriptManager
{
  ...

  public int[] loadUsrIDs(object usr_names = null) //by default if usr_names == null then return all user IDs
  {
    ...//reading the database

   return id_users.ToArray();   //from List<int> to int[]
  }

}

Unfortunately, instead of the Int array (int[]) I always get the following value ([object Promise]) - test code:

var UserID_array = window.external.loadUsrIDs(usr_names);
alert(UserID_array); //alert - only for tests

//Alert function always return value: **[object Promise]**

How do I get access to the returned data by C# method in JS?

Regards

Marcin

The documentation suggests it will always return a promise. By implication, I don't think it's checking the return type or using it at all. — Aluan Haddad, Commented Apr 14, 2018 at 0:30
developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — amaitland, Commented Apr 14, 2018 at 0:47
try using only external keyword , remove WINDOW from js method — Yash Soni, Commented Dec 3, 2018 at 20:18

Suraj Rao · Accepted Answer · 2018-12-01 11:22:32Z

0

try using

var UserID_array = await window.external.loadUsrIDs(usr_names);

edited Dec 1, 2018 at 11:22

Suraj Rao

29.6k11 gold badges96 silver badges104 bronze badges

answered Dec 1, 2018 at 11:07

Beep.exe

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Add a comment |

Woffy · Accepted Answer · 2019-03-13 06:41:33Z

You need to wait for the response.

Once you have called your C# function, assign the results to a variable (like you already have done).

Then use the then(success,failure) feature to consume the data.

var UserID_array = window.external.loadUsrIDs(usr_names);

UserID_array.then(
    function(result) {
        doSomethingWithYourData(result);            
    }, function (err) { 
        console.log(err); 
    });

This makes your page far more responsive allowing the UI to continue to respond to your users while waiting for your data.

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