在ASP.NET MVC中使用GUID作为数据库中的ID [英] Using a GUID as the ID in a database with ASP.NET MVC

问题描述

我正在学习ASP.NET MVC.我正在遵循 asp.net 上的基本教程之一.由于我并不总是按照这些教程进行操作，因此我决定使用GUID作为标识列，而不是整数.一切工作正常，直到我可以通过MVC应用程序向数据库添加新记录为止.当我添加新记录时，它插入了一个空白的GUID而不是一个生成的GUID.这是处理插入的代码段:

I am learning ASP.NET MVC. I am following one of the basic tutorials on asp.net. Since I do not always follow the tutorials to the letter, I decided to use a GUID as the identity column instead of an integer. Everything was working fine until I got up to the point of adding a new record to the database through the MVC application. When I added the new record, it inserted a blank GUID instead of a generated one. Here is the segment of code-behind that handles the insertion:

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create([Bind(Exclude = "id")]Movie movieToCreate)
{
    try
    {
        _entities.AddToMovieSet(movieToCreate);
        _entities.SaveChanges();

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

[Bind(Exclude = "id")]行忽略" ID列，因为它是自动生成的.在本教程中，ID是自动递增的，但是我认为这是因为它是一个整数.我尝试在此方法中添加一行:

The [Bind(Exclude = "id")] line 'ignores' the ID column, since it is autogenerated. In the tutorial, the ID is auto-incremented but I think that is because it is an integer. I tried adding a line to this method:

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create([Bind(Exclude = "id")]Movie movieToCreate)
{
    try
    {
        movieToCreate.id = Guid.NewGuid();
        _entities.AddToMovieSet(movieToCreate);
        _entities.SaveChanges();

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

但是ID仍然是空的GUID.谁能为我提供一些有关这是为什么以及可能如何解决的信息?

But the id is still an empty GUID. Can anyone provide me with some information on why this is and perhaps how to resolve it?

推荐答案

您可以使用自定义ModelBinder.我通过此处了解了这些信息.

You could use a custom ModelBinder. I learned about those over here.

public class MyClassBinder : DefaultModelBinder {
    protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType) {
        var model = (Movie)base.CreateModel(controllerContext, bindingContext, modelType);
        model.id = Guid.NewGuid();
        return model;
    }
}

您的动作控制者将是:

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult MyAction(Movie movieToCreate) {
    // movie should have a new guid in the id
    _entities.AddToMovieSet(movieToCreate);
    _entities.SaveChanges();
}

并且您需要在Global.asax中注册活页夹:

And you would need to register the binder in Global.asax:

protected void Application_Start() {
    RegisterRoutes(RouteTable.Routes);
    ModelBinders.Binders.Add(typeof(Movie), new MyClassBinder());
}

这篇关于在ASP.NET MVC中使用GUID作为数据库中的ID的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！