Upload Troubleshooting

The Upload component requires integration with remote endpoints and controller methods to work. Controller routing depends entirely on the app configuration. Common pitfalls may be:

• The action method is hit, but the method argument is null.
  • Make sure the action method argument names match the SaveField and RemoveField values. The default value of both parameters is "files".
  • The argument type of the SaveUrl action method should be IFormFile or IEnumerable<IFormFile>.
  • The argument type of the RemoveUrl action method should be string or IEnumerable<string>.
  • The uploaded file size may be over the web server's maximum.
• The server returns HTTP 400 Bad request.
  • Make sure that controller routing is enabled and configured correctly. For example, the controller samples in this documentation use [Route("api/[controller]/[action]")]. It is enough to add app.MapDefaultControllerRoute(); to Program.cs in the default Blazor project template.
  • Make sure that the [Route] attribute in the upload controller (if set) is compatible with SaveUrl and RemoveUrl.
  • Verify that the controller and action method names match the SaveUrl and RemoveUrl values.
• The server does not return any response. The browser console shows connection errors: Failed to load resource: net::ERR_CONNECTION_RESET or Failed to load resource: The network connection was lost.
  • The uploaded file size exceeds the web server's maximum.

See Also

• How to implement Upload controller methods
• Validation
• Events