OnPostAsync works but OnPostUploadAsync doesn't

Question

I am using razor pages with Entity Framework Core.

when I use OnPostAsync it is being called. But when I use OnPostUpdateAsync method it is not being called.

This is not being called. I have tried setting breakpoint. Even OnPostUpload doesn't work

public async Task<IActionResult> OnPostUploadAsync(List<IFormFile> MyFiles)
{
 
    int a = await Task.fromResult(0);

    return Page();
}

but when I replace it with the code below it works.

public async Task<IActionResult> OnPostAsync(List<IFormFile> MyFiles)
{
    int k = await Task.FromResult(0);

    return Page();
}

Why? And how do I fix this. Below is my cshtml code.

<form method="post" enctype="multipart/form-data">
    <input type="text" value="" asp-for="mytestmodel.Name"/>
    <input type="file" value="" multiple name="MyFiles"/>
    <input type="submit" value="Submit" />
</form>

Amit Mohanty · Answer

The OnPostUpdateAsync method is not being called because it is not a built-in Razor Pages handler method. Razor Pages provides a set of built-in handler methods that are automatically executed in response to HTTP requests, such as OnGetAsync and OnPostAsync . If you want to use a custom handler method like OnPostUploadAsync , you need to specify it explicitly in the Razor Pages @page directive. For example, if your page is called MyPage , you can specify the custom handler method like this: @page "{handler?}" @model MyPageModel

Naimish Makwana · Answer

Based on the code you provided, it seems like you are using Razor Pages with Entity Framework Core to handle file uploads. It is not clear why your OnPostUpdateAsync method is not being called, but it could be due to the way you are defining and using it in your code. In general, the OnPostUpdateAsync method is called when you submit a form with an HTTP POST request and the request handler method has the [HttpPost] attribute and the name OnPostUpdateAsync. If you want to use this method to handle file uploads, you need to ensure that the form in your Razor Page is submitting a POST request and that the name of the method matches the name in the [HttpPost] attribute. It is also worth noting that the OnPostAsync method is a general-purpose method that can be used to handle POST requests for any form submission. Therefore, it is possible that your OnPostAsync method is being called instead of OnPostUpdateAsync because it is handling the file upload request. To fix this issue, you can try renaming your OnPostUpdateAsync method to OnPostAsync and see if it gets called. Alternatively, you can add the [HttpPost] attribute to your OnPostUpdateAsync method and make sure that your form is submitting a POST request to the correct URL. You can also try removing the [HttpPost] attribute from your OnPostAsync method to see if that makes a difference. In addition, you may want to check your routing configuration to ensure that your Razor Page is correctly mapped to the correct URL and HTTP method. You can do this by checking the Page directive at the top of your Razor Page file and the configuration in your Startup.cs file. Finally, make sure that you are using the latest version of Entity Framework Core and that your file upload code is correctly handling the uploaded files. You may want to use the TryUpdateModelAsync method to update your model with the uploaded files and validate the input before saving it to the database.

freiza gen · Answer

@Amit Mohanty, Your answer worked, I added asp-page-handler="Upload" to my form, and it worked. And where can I find the list of all built-in handler methods. Thanks