Question

SpectrumContext是web.config中定义的连接。我不确定为什么这不加载。

我的字符串变量“results”引发以下错误：

类型'System.Web.Routing.RouteCollection + IgnoreRouteInternal'和类型 'System.Web.Mvc.RouteCollectionExtensions + IgnoreRouteInternal' 具有相同的简单名称'IgnoreRouteInternal'，因此不能用于同一型号。给定模型中的所有类型必须具有唯一性简单的名字。使用'NotMappedAttribute'或在代码中调用Ignore 第一个流畅的API，用于明确地从中排除属性或类型模型。

HomeController.cs

using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.Entity;
using System.Data.Entity.Core.EntityClient;
using System.Data.SqlClient;
using System.Linq;
using System.Web.Mvc;
using WebApplication1.Controllers;
using WebApplication1.DataAccessLayer;
namespace WebApplication1.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
    {
        BaseContext db1 = new BaseContext("SpectrumContext");
        string sql = "select description from dbo.workcategory where workcategoryid = 3";

        string results = db1.Database.SqlQuery<string>(sql).First();

        return View(results);
    }

    public ActionResult About()
    {
        ViewBag.Message = "Your application description page.";

        return View();
    }

    public ActionResult Contact()
    {
        ViewBag.Message = "Your contact page.";

        return View();
    }
}
}

BaseContext.cs

using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.Entity;
using System.Data.Entity.Core.EntityClient;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
`test`using WebApplication1.Controllers;

namespace WebApplication1.DataAccessLayer
{
public class BaseContext : DbContext
{
    protected string connectionName;
    public DbSet<HomeController> description { get; set; }

    /**
     * Created the connection to the server using the giving connection string name
     * 
     * @param connName
     */
    public BaseContext(string connName = "SpectrumContext")
        : base(connName)
    {
        connectionName = connName;
    }

    /**
     * Changes the default database
     * 
     * @param databaseName
     */
    public BaseContext setDatabase(string databaseName)
    {
        var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings[connectionName].ConnectionString;

        SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder(connectionString);

        //change the database before creating the new connection
        builder.InitialCatalog = databaseName;

        string sqlConnectionString = builder.ConnectionString;

        return new BaseContext(sqlConnectionString);
    }
}
}

Index.cshtml

@{
    ViewBag.Title = "Home Page";
}

<div class="jumbotron">
<h1>ASP.NET</h1>

</div>

<div>

</div>

Answer 1

为了帮助您入门，如果您只想执行简单的SQL语句，请立即抛弃（EF）DbContext，直到您了解EF的工作原理及其用途。

在学习的过程中，您可以使用原始ADO执行简单的SQL语句，如下所示：

const string sql = "select description from dbo.workcategory where workcategoryid = 3";
var connectionString = ConfigurationManager.ConnectionStrings["SpectrumContext"].ConnectionString;
using (var cn = new SqlConnection(connectionString))
{
    using (var cmd = new SqlCommand(sql, cn))
    {
        var results = Convert.ToString(cmd.ExecuteScalar());

        return View(results);
     }
}

我无法弄清楚我的实体框架MVC设置发生了什么

1 个答案: