Question

我有以下问题。我有一个项目A（Windows窗体）和项目B（MVC应用程序）。在项目A中，我引用了项目B，因为我想使用它中的一些类。有一次，我必须从项目B获得修改后的连接字符串，并连接到项目A中的数据库。

项目B中的代码，即操纵连接字符串：

public static string ConnectionString = "";
public TheClassThatManipulateTheConnectionString (){
     ConnectionString = ManageConnectionString();
}



     private string ManageConnectionString(){
             WriteToFile.WriteToTextFile("0");
             string ConfigurationString = ConfigurationManager.ConnectionStrings["DbConnectionString"].ConnectionString;
             WriteToFile.WriteToTextFile("1");
             EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder(ConfigurationString);
             WriteToFile.WriteToTextFile("2");
             DbProviderFactory factory = DbProviderFactories.GetFactory(entityBuilder.Provider);
             WriteToFile.WriteToTextFile("3");
             DbConnectionStringBuilder providerBuilder = factory.CreateConnectionStringBuilder();
             WriteToFile.WriteToTextFile("4");
             providerBuilder.ConnectionString = entityBuilder.ProviderConnectionString;
             WriteToFile.WriteToTextFile("5");
             providerBuilder.Add("Password", "ThePassword");
             WriteToFile.WriteToTextFile("6");
             entityBuilder.ProviderConnectionString = providerBuilder.ToString();
             WriteToFile.WriteToTextFile("7");
             return entityBuilder.ToString();
        }

项目A中的代码，即调用Project B方法：

public Form1(){
    InitializeComponent();
    ProjectB.Folder.Folder.TheClassThatManipulateTheConnectionString TheClassThatManipulateTheConnectionString = new ProjectB.Folder.Folder.TheClassThatManipulateTheConnectionString ();
    using (ProjectB.Folder.Folder.Context db = new ProjectB.Folder.Folder.Context TheClassThatManipulateTheConnectionString.TheConnectionString))
                    { }
}

Exceoption与track code一起写入文件。

'08/06/2014 21:29:35: 0
 08/06/2014 21:29:35:  Exception: System.NullReferenceException: Object reference not set to an instance of an object.'

项目A的例外

at System.Data.Entity.Utilities.Check.NotEmpty(String value, String parameterName)
   at System.Data.Entity.DbContext..ctor(String nameOrConnectionString)
   at ProjectB.Folder. Folder.Context..ctor(String ConnectionString) in c:\Users\Administrator\Documents\Visual Studio 2013\Projects\ ProjectB \ ProjectB \ Folder \ Folder \DBEntities.Context.cs:line 20
   at ProjectA.Form1.FillUsers() in c:\Users\Administrator\Documents\Visual Studio 2013\Projects\ ProjectA\ ProjectA \Form1.cs:line 51

在文字文件中，我可以看到0，但不是1。我的问题是，当将配置管理器调用到项目A中时，为什么配置管理器无法正常工作。

如何在另一个项目中使用配置设置？

0 个答案: