What is the difference between InvokeVoidAsync and InvokeAsync JsRuntime?-CodePudding

What are the differences between these two and which one should I use?

await JsRuntime.InvokeVoidAsync()
await JsRuntime.InvokeAsync()`

CodePudding user response：

InvokeVoidAsync

Use InvokeVoidAsync when:

.NET isn't required to read the result of a JavaScript (JS) call.
JS functions return void(0)/void 0 or undefined.

For example the below function can call with InvokeVoidAsync and doesn't return a value:

<script>
  window.displayTickerAlert1 = (symbol, price) => {
    alert(`${symbol}: $${price}!`);
  };
</script>

And you can use this in a component by following code:

await JS.InvokeVoidAsync("displayTickerAlert1", stockSymbol, price);

InvokeAsync

Use InvokeAsync when .NET should read the result of a JavaScript (JS) call.

The following example returns a string for display by the caller:

<script>
  window.displayTickerAlert2 = (symbol, price) => {
    if (price < 20) {
      alert(`${symbol}: $${price}!`);
      return "User alerted in the browser.";
    } else {
      return "User NOT alerted.";
    }
  };
</script>

And you can use of this to a component such as below:

 var interopResult = 
            await JS.InvokeAsync<string>("displayTickerAlert2", stockSymbol, price);
        result = $"Result of TickerChanged call for {stockSymbol} at "  
            $"{price.ToString("c")}: {interopResult}";

Please note that you have to inject IJSRuntime on the above of the component, such as below:

@inject IJSRuntime JS

You can refer to Calling JavaScript from .NET and call-javascript-from-dotnet for more info.

CodePudding user response：

await JsRuntime.InvokeVoidAsync() executes Javascript function and this function do not return any value to C# code

await JsRuntime.InvokeAsync() also execute Javascript function but can return some value to C# code