Asp.Net Core 3.1 数据被检索但未保存到数据库中

Question

I am creating an Asp.Net core web application. I have successfully connected database to my app. I can run all the migration successfully and even retrieve data from database. But when I try to save data using my DbContext data is not saved in the database. Here is my code

Category Model Class

public class Category
{
    public int Id { get; set; }
    public string Name { get; set; }
}

Category Controller

public class CategoryController : Controller
{
    private readonly AppDbContext dbContext;

    public CategoryController(AppDbContext dbContext)
    {
        this.dbContext = dbContext;
    }

    [HttpGet]
    public IActionResult Index()
    {
        var categories = dbContext.Categories.ToList();
        return View(categories);
    }

    [HttpGet]
    public IActionResult Create()
    {
        return View();
    }

    [HttpPost]
    public IActionResult Create(Category category)
    {
        if (ModelState.IsValid)
        {
            dbContext.Categories.Add(category);
            return RedirectToAction(nameof(Index));
        }
        return View();
    }
}

View

<form asp-action="Create">
        <div asp-validation-summary="ModelOnly" class="text-danger"></div>
        <div class="form-group">
            <label asp-for="Name" class="control-label"></label>
            <input asp-for="Name" class="form-control" />
            <span asp-validation-for="Name" class="text-danger"></span>
        </div>
        <div class="form-group">
            <input type="submit" value="Create" class="btn btn-primary" />
        </div>
 </form>

DbContext Class

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
    {

    }

    public DbSet<Category> Categories { get; set; }
}

and finally my ConfigureServices Method in Startup file

public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllersWithViews();

        services.AddDbContext<AppDbContext>(options => options
        .UseLazyLoadingProxies()
        .UseSqlServer(Configuration.GetConnectionString("AppDbContext")));
    }

I successfully get data in the Index method that I have manually stored in database but cannot save from a form.

Answer 1

It is necessary to call SaveChanges() method of EntityFramework to save data:

dbContext.Categories.Add(category);
dbContext.SaveChanges();

It is necessary to call SaveChanges after creating, updating, deleting operations.

Answer 2

In Entity Framework, the DbContext.SaveChanges() method saves all changes made in the context of the database.

So after adding, updating or deleting data you need call SaveChages() method:

dbContext.Categories.Add(category);
dbContext.SaveChanges();

for knowing more about SaveChange() you can follow this link .