How to force a component to re-render?

To force a component to rerender, use the “StateHasChanged” method in Blazor, to notify that the state has been changed and requires re-rendering. For more information on the same, check this link.

How to detect keypress event without using an input tag?

To detect keypress event in a div tag, use the @onkeydown event on the current element. In the created example there is a div element with keydown event, and on rendering, the focus to the div element is set by using the JS Interop.

How do I do server-side form validation?

To carry out form validation in a Blazor server-side application, use data annotations to enable validation for the forms. Also, include <DataAnnotationsValidator  /> and <ValidationSummary /> in the forms. Refer to the following code sample.