blazor - "Object reference not set to an instance of an object" while using bind

Question

html:

<input @bind="title"/>

<div id="chat-bottom-button-right-row">                
  <button @onclick="(() => RunMovie(title))">Chat</button> //I'd like to use title from input
</div>

c# code:

[Inject]
    public IJSRuntime Js { get; set; }
    private MovieDataDetail movieDetail = null;

    string title;
    private async Task RunMovie(string title)
    {
        movieDetail = await TmdbApi.GetAllMovieInfo(title); //Object reference not set to an instance of an object
        await Js.InvokeVoidAsync("kinX").AsTask();
    }

I'd like to use title from input.

title always null even if I write something to input

question from:https://stackoverflow.com/questions/65868601/object-reference-not-set-to-an-instance-of-an-object-while-using-bind

Answer 1

If you want two-way binding (i.e. the input is populated from the variable AND the variable is updated by the input) then use:

<input @bind-value=@title />