How to close a bootstrap Modal from a blazor webassembly component code?

Question

I was trying to find a way to close a bootstrap modal from a C# method inside a blazor webassembly component.

Bellow is a solution I came up with. It involves the use of IJSRuntime to call a javascript method to manipulate the bootstrap modal. I'm sure there are other ways to solve this.

Answer 1

The bootstrap modal can be closed via javascript:

Create a javascript wwwroot/js/site.js file with the code:

export function CloseModal(modalId) {
    $(modalId).modal('hide');
}

Include the script in index.html at the end of the body:

...
<script src="js/site.js"></script>
</body>

There exists a parent component calling the modal:

ParentComponent.razor

<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal">
  Launch demo modal
</button>

<ModalComponent />

@code {

}

Then there is a modal component containing the modal: (We are making use of IJSRuntime to call js from C# code)

ModalComponent.razor

@inject IJSRuntime js

<!-- Modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

@code {

    IJSObjectReference JsObjectRef { get; set; }
    protected override async Task OnAfterRenderAsync(bool first)
    {
        JsObjectRef = await js.InvokeAsync<IJSObjectReference>("import", "/js/site.js");
    }
    
    async Task SomeMethod(){
     
    //some logic

    //call the js function to close the modal
    await JsObjectRef.InvokeVoidAsync("CloseModal", "#exampleModal");


    }
}

Now the modal can be closed from the c# code, say for example when a submit method is called.

This logic has worked for me. I'm sure there are other better solutions for this out there, nevertheless I really hope it helps anyone in need.

Peace