我一直在使用新的MVCScaffolding作为我的下一个CMS，到目前为止它已经很棒了。很棒，直到我想将我的SQLExpress默认数据库更改为SQLCe本地数据库。
这里（http://blog.stevensanderson.com/2011/01/13/scaffold-your-aspnet-mvc-3-project-with-the-mvcscaffolding-package/）它表示，如果我安装“EFCodeFirst.SqlServerCompact”软件包，它将负责更改它甚至创建数据库文件。所以我做到了。
它创建了一个名为“SQLCEEntityFramework.cs”的文件，该文件中存在一些错误。就像对“System.Data.Entity.Database”的引用不再存在，现在引用DbDatabase Database。所以我修复了这些错误并运行了应用程序。
所有内容都照常运行，但没有连接字符串添加到我的Web.config，并且我的App_Data目录中没有创建数据库文件。所以现在我开始怀疑自己做错了什么......
任何人都知道这里发生了什么以及如何解决它？
非常感谢。
编辑：以防万一你想看看SQLCEEntityFramework.cs文件中的内容：
using System;
using System.Data.Entity;
using System.Data.SqlServerCe;
using System.IO;
using System.Transactions;
using System.Data.Entity.Infrastructure;
[assembly: WebActivator.PreApplicationStartMethod(typeof(CMS.App_Start.SQLCEEntityFramework), "Start")]
namespace CMS.App_Start {
public static class SQLCEEntityFramework {
public static void Start() {
Database.DefaultConnectionFactory = new SqlCeConnectionFactory("System.Data.SqlServerCe.4.0");
// Sets the default database initialization code for working with Sql Server Compact databases
// Uncomment this line and replace CONTEXT_NAME with the name of your DbContext if you are
// using your DbContext to create and manage your database
//DbDatabase.SetInitializer(new CreateCeDatabaseIfNotExists<CONTEXT_NAME>());
}
}
public abstract class SqlCeInitializer<T> : IDatabaseInitializer<T> where T : DbContext {
public abstract void InitializeDatabase(T context);
#region Helpers
/// <summary>
/// Returns a new DbContext with the same SqlCe connection string, but with the |DataDirectory| expanded
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
protected static DbContext ReplaceSqlCeConnection(DbContext context) {
if (context.Database.Connection is SqlCeConnection) {
SqlCeConnectionStringBuilder builder = new SqlCeConnectionStringBuilder(context.Database.Connection.ConnectionString);
if (!String.IsNullOrWhiteSpace(builder.DataSource)) {
builder.DataSource = ReplaceDataDirectory(builder.DataSource);
return new DbContext(builder.ConnectionString);
}
}
return context;
}
private static string ReplaceDataDirectory(string inputString) {
string str = inputString.Trim();
if (string.IsNullOrEmpty(inputString) || !inputString.StartsWith("|DataDirectory|", StringComparison.InvariantCultureIgnoreCase)) {
return str;
}
string data = AppDomain.CurrentDomain.GetData("DataDirectory") as string;
if (string.IsNullOrEmpty(data)) {
data = AppDomain.CurrentDomain.BaseDirectory ?? Environment.CurrentDirectory;
}
if (string.IsNullOrEmpty(data)) {
data = string.Empty;
}
int length = "|DataDirectory|".Length;
if ((inputString.Length > "|DataDirectory|".Length) && ('\\' == inputString["|DataDirectory|".Length])) {
length++;
}
return Path.Combine(data, inputString.Substring(length));
}
#endregion
}
/// <summary>
/// An implementation of IDatabaseInitializer that will recreate and optionally re-seed the
/// database only if the database does not exist.
/// To seed the database, create a derived class and override the Seed method.
/// </summary>
/// <typeparam name="TContext">The type of the context.</typeparam>
public class CreateCeDatabaseIfNotExists<TContext> : SqlCeInitializer<TContext> where TContext : DbContext {
#region Strategy implementation
public override void InitializeDatabase(TContext context) {
if (context == null) {
throw new ArgumentNullException("context");
}
var replacedContext = ReplaceSqlCeConnection(context);
bool databaseExists;
using (new TransactionScope(TransactionScopeOption.Suppress)) {
databaseExists = replacedContext.Database.Exists();
}
if (databaseExists) {
// If there is no metadata either in the model or in the databaase, then
// we assume that the database matches the model because the common cases for
// these scenarios are database/model first and/or an existing database.
if (!context.Database.CompatibleWithModel(throwIfNoMetadata: false)) {
throw new InvalidOperationException(string.Format("The model backing the '{0}' context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance. For example, the DropCreateDatabaseIfModelChanges strategy will automatically delete and recreate the database, and optionally seed it with new data.", context.GetType().Name));
}
}
else {
context.Database.Create();
Seed(context);
context.SaveChanges();
}
}
#endregion
#region Seeding methods
/// <summary>
/// A that should be overridden to actually add data to the context for seeding.
/// The default implementation does nothing.
/// </summary>
/// <param name="context">The context to seed.</param>
protected virtual void Seed(TContext context) {
}
#endregion
}
/// <summary>
/// An implementation of IDatabaseInitializer that will <b>DELETE</b>, recreate, and optionally re-seed the
/// database only if the model has changed since the database was created. This is achieved by writing a
/// hash of the store model to the database when it is created and then comparing that hash with one
/// generated from the current model.
/// To seed the database, create a derived class and override the Seed method.
/// </summary>
public class DropCreateCeDatabaseIfModelChanges<TContext> : SqlCeInitializer<TContext> where TContext : DbContext {
#region Strategy implementation
/// <summary>
/// Executes the strategy to initialize the database for the given context.
/// </summary>
/// <param name="context">The context.</param>
public override void InitializeDatabase(TContext context) {
if (context == null) {
throw new ArgumentNullException("context");
}
var replacedContext = ReplaceSqlCeConnection(context);
bool databaseExists;
using (new TransactionScope(TransactionScopeOption.Suppress)) {
databaseExists = replacedContext.Database.Exists();
}
if (databaseExists) {
if (context.Database.CompatibleWithModel(throwIfNoMetadata: true)) {
return;
}
replacedContext.Database.Delete();
}
// Database didn't exist or we deleted it, so we now create it again.
context.Database.Create();
Seed(context);
context.SaveChanges();
}
#endregion
#region Seeding methods
/// <summary>
/// A that should be overridden to actually add data to the context for seeding.
/// The default implementation does nothing.
/// </summary>
/// <param name="context">The context to seed.</param>
protected virtual void Seed(TContext context) {
}
#endregion
}
/// <summary>
/// An implementation of IDatabaseInitializer that will always recreate and optionally re-seed the
/// database the first time that a context is used in the app domain.
/// To seed the database, create a derived class and override the Seed method.
/// </summary>
/// <typeparam name="TContext">The type of the context.</typeparam>
public class DropCreateCeDatabaseAlways<TContext> : SqlCeInitializer<TContext> where TContext : DbContext {
#region Strategy implementation
/// <summary>
/// Executes the strategy to initialize the database for the given context.
/// </summary>
/// <param name="context">The context.</param>
public override void InitializeDatabase(TContext context) {
if (context == null) {
throw new ArgumentNullException("context");
}
var replacedContext = ReplaceSqlCeConnection(context);
if (replacedContext.Database.Exists()) {
replacedContext.Database.Delete();
}
context.Database.Create();
Seed(context);
context.SaveChanges();
}
#endregion
#region Seeding methods
/// <summary>
/// A that should be overridden to actually add data to the context for seeding.
/// The default implementation does nothing.
/// </summary>
/// <param name="context">The context to seed.</param>
protected virtual void Seed(TContext context) {
}
#endregion
}
}
答案 0 :(得分：0)
汤姆，
我也遇到过Sql CE和Entity Framework的问题。但是，我或许能够解释你所引用的帖子，因为我已经精通使用它，因为我已经通过它进行了战斗。
首先，该博客文章是针对MVCScaffolding NuGet包的。不知道你是否知道这个套装的功能，但它基本上增加了对Scott＆amp; Sons的脚手架的参考。创建公司以在构建模型后为您动态生成CRUD。
我的理解是，一旦你创建了一个模型，构建你的项目，你就可以在Package Manager Console中运行以下命令，它将创建我上面提到的CRUD。
Scaffold Controller [WhateverYourModelNameIs]
现在，一旦完成此过程，它将在Models文件夹下为您的应用程序生成一个Context类。如果你在Start方法的代码中看到了上面的代码（对于SQLCEEntityFramework.cs），它会提到你需要取消注释方法的最后一行，以便它创建db（如果它不存在）。
最后，一旦执行了应用程序，就应该“创建”SQL CE数据库，如果单击App_Data文件夹并选择解决方案资源管理器顶部的“显示所有文件”并点击“刷新”图标，应该看到你的数据库。
<强>更新
很抱歉，经过测试，汤姆，你是对的。创建数据库的唯一方法是执行Scaffolder创建的其中一个视图。