以编程方式创建一个连接字符串，用于将Entity Framework Code-First模型与现有的Sql Server Compact数据库进行映射 [英] Programmatically creating a connection string for mapping an Entity Framework Code-First model with an existing Sql Server Compact database

问题描述

我已经使用 app.config 以声明方式成功映射了一个具有现有Sql Server Compact数据库的Entity Framework Code-First数据模型，但是如果我可以通过 EntityConnectionStringBuilder （System.Data.EntityClient）类的帮助，以编程方式来构建这种连接。不幸的是，这种方法不起作用，因为 [DbContext] .Connection.ConnectionString 不接受其大部分属性。

I've successfully mapped an Entity Framework Code-First data model with an existing Sql Server Compact database by a declarative approach using app.config but it would be great if I could build such connection programmatically with perhaps the help of the EntityConnectionStringBuilder (System.Data.EntityClient) class. Unfortunately this approach is not working as the [DbContext].Connection.ConnectionString is not accepting most of its properties.

以下是有错误的实际工作代码：

Here's the actual working code with the faulty one commented out:

Book.cs

public class Book
{
    [Key]
    public string Isbn { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public string Publisher { get; set; }
    public DateTime Published { get; set; }
    public int Pages { get; set; }
    public bool InStock { get; set; }
    public string Description { get; set; }
}

Catalog.cs

public class Catalog : DbContext
{
    public DbSet<Book> Books { get; set; }
}

app.config

<?xml version="1.0"?>
<configuration>
  <connectionStrings>
    <add
      name="Catalog"
      providerName="System.Data.SqlServerCE.4.0"
      connectionString="Data Source=res/Catalog.sdf"
  />
  </connectionStrings>
</configuration>

Main（）

static void Main()
{
    // var res = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), "res");
    // var str = new EntityConnectionStringBuilder();
    // str.Name = "Catalog";
    // str.Provider = "System.Data.SqlServerCe.4.0";
    // str.ProviderConnectionString = String.Format("Data Source {0}", Path.Combine(res, "Catalog.sdf"));

    try
    {
        using (var catalog = new Catalog())
        {
            // catalog.Database.Connection.ConnectionString = str.ConnectionString;

    // remaining code not relevant - skipped

我尝试使用其他构建器类，如 SqlCeConnectionStringBuilder （System.Data.SqlServerCe）， SqlConnectionStringBuilder （System.Data.SqlClient）甚至 DbConnectionStringBuilder （System.Data.Common），但显然他们似乎没有匹配什么 [DbContext] .Connection.ConnectionString 期待。

I've tried using other builder classes such as SqlCeConnectionStringBuilder (System.Data.SqlServerCe), SqlConnectionStringBuilder (System.Data.SqlClient) and even DbConnectionStringBuilder (System.Data.Common) but apparently none of them seem to match what [DbContext].Connection.ConnectionString is expecting.

我应该得出结论，没有程序化的方式来实现这一点？
任何建议一定会受到赞赏。非常感谢您的贡献。

Should I conclude there is no programmatic way to achieve this? Any advice will be surely appreciated. Thanks much in advance for your contributions.

推荐答案

如果您使用SQL Server Compact 4.0和 DbContext 代码首先你不能使用 EntityConnectionStringBuilder - 它使用EDMX文件构建EF的连接字符串。您需要 SqlCeConnectionStringBuilder 从 System.Data.SqlServerCe 版本4.0.0.0的程序集！

If you are using SQL Server Compact 4.0 and DbContext with code first you cannot use EntityConnectionStringBuilder - it builds connection string for EF with EDMX file. You need SqlCeConnectionStringBuilder from System.Data.SqlServerCe assembly with version 4.0.0.0!

您还应该通过构造函数将连接字符串传递给上下文实例 - DbContext 具有构造函数接受的名称连接字符串（从配置）或连接字符串本身。

You should also pass the connection string to the context instance through the constructor - DbContext has constructor accepting name of the connection string (from configuration) or connection string itself.

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