EntityFramework Core自动生成密钥id属性

Question

使用.Net Core MVC.我需要设置我的模型,以便EntityFrameworkCore将自动生成ID属性.我认为只需添加[Key]注释即可,但事实并非如此.事实上,当ID字段留空时会产生错误,这总是因为我将其隐藏在用户之外.

我需要它来代替每次为模型自动生成一个唯一的ID.我该怎么做呢？我的ID属性目前是类型int.

ExampleModel

public class ExampleModel
{
    [Key]
    public int ID { get; set; }
    public string SomeData { get; set; }
}

ExampleView

@model MyNamespace.Models.ExampleModel

<form asp-action="Create" asp-controller="ExampleModel">
    @Html.EditorForModel()
    <input type="submit" name="Submit" value="Create"/>
</form>

ExampleController

public IActionResult Create ()
{
    return View();
}
public IActionResult Create (ExampleModel model)
{
    if (ModelState.IsValid)
    {
        _context.ExampleModels.Add(model);
        _context.SaveChanges();
        return RedirectToAction("Index");
    }

    return View(model);
}

Answer 1

您需要更改自己的数据注释,ExampleModel以便自动生成唯一ID.

ExampleModel

public class ExampleModel
{
    [ScaffoldColumn(false)]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ID { get; set; }

    public string SomeData { get; set; }
}