C# EF Code first - 创建数据库和添加数据

Question

我想创建数据库并添加一些数据。我添加了 EF，我想先使用代码。我有这些类(class):

public class Question
{
    public bool Sort { get; set; }
    public int QuestionID { get; set; }
    public int Level { get; set; }
    public string Description { get; set; }
    public string Answer1 { get; set; }
    public string Answer2 { get; set; }
    public string Answer3 { get; set; }
    public string Answer4 { get; set; }
    public string RightAnswer { get; set; }
    public bool Show { get; set; }
}

public class QuestionDb : DbContext
{
    public DbSet<Question> Questions { get; set; }
}

这是我的连接字符串:

<add name="ConvertCSVtoSQL.QuestionDb" connectionString="Data Source=|DataDirectory|ConvertCSVtoSQL.QuestionDb.sdf"
      providerName="System.Data.SqlServerCe.4.0" />

现在我正在创建这样的数据库:

using (var db = new QuestionDb())
        {

            foreach (var question in questions)
            {
                db.Questions.Add(question);
            }
            db.SaveChanges();
        }

它会创建数据库，但如果我在问题中有一些数据要添加，我会收到错误消息:

The Entity Framework provider type 'System.Data.Entity.SqlServerCompact.SqlCeProviderServices, EntityFramework.SqlServerCompact, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' for the 'System.Data.SqlServerCe.4.0' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.

我尝试添加一些初始值设定项，但没有帮助:

Database.DefaultConnectionFactory = new SqlCeConnectionFactory("System.Data.SqlServerCe.4.0",@"C:\Path\To\",@"Data Source=C:\Path\To\DbFile.sdf");
Database.SetInitializer(new CreateDatabaseIfNotExists<QuestionDb>());

那么问题出在哪里呢？

Answer 1

我查看了异常链接，将 nuget 包 EntityFramework.SqlServerCompact 添加到我的解决方案中，这很有帮助。