EF Code First 的动态连接字符串

Question

我当前位于 Web.config 中的连接字符串是这样的：

  <add name="PersonDBContext" 
       connectionString="Server=111.111.1.11;
       Database=MyProgram;
       User Id=admin;
       Password=12345;
       Integrated Security=False" 
       providerName="System.Data.SqlClient" />

我想以动态的方式给程序提供相同的连接字符串，这是我的尝试：

    EntityConnectionStringBuilder csb = new EntityConnectionStringBuilder();

    csb.ProviderConnectionString = "Data Source=111.111.1.11;Initial Catalog=MyProgram;User Id=admin;Password=12345;Integrated Security=False";
    csb.Provider = "System.Data.SqlClient";

    String entityConnStr = csb.ToString();
    return entityConnStr;

这就是我得到的：

不支持关键字：'provider'。

你能告诉我我做错了什么吗？ 我需要 Code First 连接字符串的元数据吗？谢谢。

编辑： 我认为我要么不应该使用 EntityConnectionStringBuilder，要么应该为 EntityConnectionStringBuilder 类提供元数据。你能告诉我如何做到这一点的方法之一吗？

Answer 1

为什么不在 DbContext 派生类的构造函数中将其作为纯字符串传递？ 喜欢

var ctx = new MyContext("Data Source=111.111.1.11;Initial Catalog=MyProgram;User Id=admin;Password=12345;Integrated Security=False");

Answer 2

为了让用户能够键入或选择他们想要连接的服务器，我必须做以下事情：

在 EF 创建的 Model.Context.cs 文件中，我将构造函数更改为：

public partial class Entities : DbContext
{
    public Entities()
        : base(BuildConnectionString)
    {
    }
    ...
}

然后我写了一个扩展类EntitiesEx.cs

partial class Entities : DbContext
{
    private static string BuildConnectionString 
    {
        get
        {
            // Specify the provider name, server and database.
            string providerName = "System.Data.SqlClient";
            string serverName = DatabaseController.Server;
            string databaseName = <DatabaseName>;

            // Initialize the connection string builder for the
            // underlying provider.
            SqlConnectionStringBuilder sqlBuilder = new SqlConnectionStringBuilder();

            // Set the properties for the data source.
            sqlBuilder.DataSource = serverName;
            sqlBuilder.InitialCatalog = databaseName;

            sqlBuilder.UserID = <user>;
            sqlBuilder.Password = <password>;

            sqlBuilder.IntegratedSecurity = false;

            sqlBuilder.PersistSecurityInfo = true;

            sqlBuilder.MultipleActiveResultSets = true;

            // Build the SqlConnection connection string.
            string providerString = sqlBuilder.ToString();

            // Initialize the EntityConnectionStringBuilder.
            EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();

            //Set the provider name.
            entityBuilder.Provider = providerName;

            // Set the provider-specific connection string.
            entityBuilder.ProviderConnectionString = providerString;

            //assembly full name
            Type t = typeof(Entities);
            string assemblyFullName = t.Assembly.FullName.ToString();

            // Set the Metadata location.
            entityBuilder.Metadata = string.Format("res://{0}/", //Models.Model.csdl|Models.Model.ssdl|Models.Model.msl", 
                assemblyFullName);

            try
            {
                //Test de conexion
                using (EntityConnection conn = new EntityConnection(entityBuilder.ToString()))
                {
                    conn.Open();

                    conn.Close();
                }
            }
            catch (Exception ex)
            {
                throw new Exception("Connection error" + ex.Message);
            }

            return entityBuilder.ToString();
        }
    }

作为一个缺点，每次从数据库生成模型时，都必须更改 Entities 类 (Model.Context.cs) 中的构造函数

Answer 3

Code First 的动态连接字符串使用简单的 sql 连接字符串或不使用 EntityConnectionStringBuilder。所以你可以通过以下方式实现它。

public static string  DynamicConnectionString(SqlConnectionStringBuilder builder)
{
    SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
    builder.DataSource = "ServerName";
    builder.InitialCatalog = "DatabaseName";
    builder.UserID = "UserId";
    builder.Password = "Password";
    builder.MultipleActiveResultSets = true;
    builder.PersistSecurityInfo = true;    
    return builder.ConnectionString.ToString();
}

Answer 4

原来是这样的：

string entityConnStr = "Data Source=111.111.1.11;Initial Catalog=MyProgram;User Id=admin;Password=12345;Integrated Security=False";