如何首先覆盖 EF 代码中的“不可见”连接字符串？

Question

我首先通过代码使用 EF 6.1.2 编写了我的应用程序。输入命令“更新数据库”后，数据库已在我的 Microsoft SQL Server 2017 中创建。到目前为止一切顺利。但是我从未在我的 app.config （来自类库）中看到到我的数据库的连接字符串。它只是不存在，但是，令我惊讶的是它有效。它完美地连接到我的本地服务器。

现在，我已将数据库移至云端，因此我有一个连接字符串。我已将连接字符串复制粘贴到应用程序配置中，但它仍然指向初始服务器。

我的 app.config 看起来像这样：

 <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <configSections>
        <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
       <!--For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468--> 
      </configSections>
      <entityFramework>
        <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
        <providers>
          <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
        </providers>
      </entityFramework>
    </configuration>
    

我尝试放置连接字符串，但没有效果。它仍然指向本地服务器。我什至删除了所有内容，并粘贴了我的连接字符串，但没有成功。

关于如何添加连接字符串以使其指向云中的数据库有什么想法吗？

更新： Roman 请求的 web.config。我已将连接字符串放在那里，但没有什么区别（是的，我知道“X”，我不想共享数据库:-)）：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>

  <connectionStrings>
    <add name="freeaspconnection" connectionString="Server=XXXX;Database=XXXXXX;uid=liviusosu;pwd=;" providerName="System.Data.SqlClient" />
  </connectionStrings>
  
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
    <add key="NumberOfUserTasksPerPage" value="7" />
    <add key="NumberOfArticlesPerPage" value="10" />
    <add key="NumberOfCoursesPerPage" value="10" />
    <add key="NumberOfJobAnnouncementsPerPage" value="30" />
    <add key="NumberOfInterviewQuestionsPerPage" value="30" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" maxRequestLength="1048576" />
    <authentication mode="Forms">
      <forms loginUrl="User/LogIn" timeout="300" />
    </authentication>
  </system.web>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>

</configuration>

这是 DBContext

public class CareerTrackContext : DbContext
{
    public CareerTrackContext()
        : base("CareerTrack")
    {

    }

    public DbSet<User> Users { get; set; }
    public DbSet<Article> Articles { get; set; }
    public DbSet<UserTask> UserTasks { get; set; }
    public DbSet<Role> Roles { get; set; }
    public DbSet<Company> Companies { get; set; }
    public DbSet<Course> Courses { get; set; }
    public DbSet<Book> Books { get; set; }
    public DbSet<Review> Reviews { get; set; }
    public DbSet<Location> Locations { get; set; }
    public DbSet<JobAnnouncement> JobAnnouncements { get; set; }
    public DbSet<Skill> Skills { get; set; }
    public DbSet<InterviewQuestion> InterviewQuestions { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
        modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();

        modelBuilder.Properties()
            .Where(p => p.Name == p.ReflectedType.Name + "Id")
            .Configure(p => p.IsKey());

        modelBuilder.Properties<string>()
            .Configure(p => p.HasColumnType("varchar"));

        modelBuilder.Properties<string>()
            .Configure(p => p.HasMaxLength(1000));

        modelBuilder.Entity<JobAnnouncement>()
           .HasMany(c => c.Skills).WithMany(i => i.JobAnnouncements)
           .Map(t => t.MapLeftKey("JobAnnouncementId")
               .MapRightKey("SkillId")
               .ToTable("JobAddsSkills"));

        modelBuilder.Configurations.Add(new UserConfiguration());
        modelBuilder.Configurations.Add(new ArticleConfiguration());
        modelBuilder.Configurations.Add(new UserTaskConfiguration());
        modelBuilder.Configurations.Add(new RoleConfiguration());
        modelBuilder.Configurations.Add(new CompanyConfiguration());
        modelBuilder.Configurations.Add(new CourseConfiguration());
        modelBuilder.Configurations.Add(new BookConfiguration());
        modelBuilder.Configurations.Add(new ReviewConfiguration());
        modelBuilder.Configurations.Add(new LocationConfiguration());
        modelBuilder.Configurations.Add(new JobAnnouncementConfiguration());
        modelBuilder.Configurations.Add(new SkillConfiguration());
        modelBuilder.Configurations.Add(new IntreviewQuestionConfiguration());

        base.OnModelCreating(modelBuilder);
    }

    public override int SaveChanges()
    {
        foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("DateRegistered") != null))
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("DateRegistered").CurrentValue = DateTime.Now;
            }

            if (entry.State == EntityState.Modified)
            {
                entry.Property("DateRegistered").IsModified = false;
            }
        }

        foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("DateAdded") != null))
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("DateAdded").CurrentValue = DateTime.Now;
            }

            if (entry.State == EntityState.Modified)
            {
                entry.Property("DateAdded").IsModified = false;
            }
        }

        foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("IsActive") != null))
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("IsActive").CurrentValue = true;
            }
        }

        foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("IsRead") != null))
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("IsRead").CurrentValue = false;
            }
        }

        foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("Status") != null))
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("Status").CurrentValue = "New";
            }
        }
        return base.SaveChanges();
    }
}

Answer 1

实体框架将在没有连接字符串的情况下工作，尽管我更希望能够进行控制以避免类似的情况并进行web.config转换。

如果您在上下文构造函数中未提供任何内容，如果本地安装了 SQL Express，您将获得一个 SQL Express 数据库（.\SqlExpress 实例）。否则，您将在用户配置文件文件夹或 \App_Data 文件夹中获得 localDb。我相信数据库是根据上下文命名的。

如果您在构造函数中提供名称，它将查找该名称的连接字符串，但如果找不到，它将遵循上述规则，但将构造函数值分配为数据库的名称。这就是你目前的情况。

所以简而言之（为时已晚），要解决您的问题，请将上下文构造函数更改为连接字符串的名称。

public CareerTrackContext()
    : base("freeaspconnection")
{

}

有关 EF 如何连接的信息，请参阅此处。