Revision history [back]

Here are the steps to utilize MediatR to modify a singular entry in a database:

1. Create a request class - this will contain the necessary information needed to modify the database entry.

public class UpdateEntryRequest : IRequest<bool>
{
    public int Id { get; set; }
    public string UpdatedData { get; set; }
}

1. Create a handler class - this will handle the request and use a repository class to perform the actual update on the database.

public class UpdateEntryHandler : IRequestHandler<UpdateEntryRequest, bool>
{
    private readonly IRepository _repository;

    public UpdateEntryHandler(IRepository repository)
    {
        _repository = repository;
    }

    public async Task<bool> Handle(UpdateEntryRequest request, CancellationToken cancellationToken)
    {
        var entry = await _repository.GetEntryById(request.Id);

        if (entry == null)
            return false;

        entry.Data = request.UpdatedData;

        return await _repository.SaveChangesAsync() > 0;
    }
}

1. Register the request and handler in your application's dependency injection setup.

services.AddTransient<IRequestHandler<UpdateEntryRequest, bool>, UpdateEntryHandler>();

1. Finally, in your controller or service layer, you can use MediatR to send the request to the handler for processing.

public class MyController : Controller
{
    private readonly IMediator _mediator;

    public MyController(IMediator mediator)
    {
        _mediator = mediator;
    }

    public async Task<IActionResult> UpdateEntry(int id, string updatedData)
    {
        var request = new UpdateEntryRequest { Id = id, UpdatedData = updatedData };
        var result = await _mediator.Send(request);

        if (result)
            return Ok();
        else
            return NotFound();
    }
}

This is an example of how to utilize MediatR to modify a singular entry in a database. It's important to note that the above code is just an example and will need to be tailored to meet the specific needs of your application.