Blazor JS Interop call confusion

Question

The following has two syntax errors of wrong type, however, I can't find any documentation on how this should be used and what I'm doing wrong. What parameters am I suppose to give this open function?

    Syntax error 1 - Argument 2: cannot convert from 'string' to 'System.Threading.CancellationToken'   
    Syntax error 2 - Argument 3: cannot convert from 'string' to 'object[]' 

private async Task HelloWorld()
{
       string url = "https://www.google.com";
       await JSRuntime.InvokeAsync<object>("open", url, "_blank");
}

Answer 1

JSRuntime is an abstract class with no static method so you can not call InvokeAsync method of the class itself. To execute javascript you have to inject an IJSRuntime object :

public class MyClass{
  
 private readonly IJSRuntime js;
 public MyClass(IJSRuntime js){
       this.js=js;
   }

    private async Task HelloWorld()
    {
           string url = "https://www.google.com";
           await js.InvokeAsync<object>("open", url, "_blank");
    }
}

Answer 2

It is a bit tricky to tell what is really going on without seeing more of your code, both on the JS side and on the razor side. However, here is a simple example of calling a JS function within your C# code. Btw, I am assuming (hopefully correctly!) that you are doing this within a component, because they code is slightly different for calling this in a class. Also, it would be helpfult to see what, if anything, you are returning from the JS method:

C#

@inject IJSRuntime JSRuntime

@code {
    private async Task HelloWorld()
    {
        string url = "https://www.google.com";
        await JSRuntime.InvokeAsync<object>("open", url, "_blank");
    }
}

JS

<script>
    window.open = function (url, target) {
        console.log(url, target)
    }
</script>