为什么 LINQ 突然开始对数据库连接表现得很奇怪

发布于 2024-08-19 23:30:12 字数 440 浏览 4 评论 0原文

这是一个奇怪的现象。突然，当我在 Visual Studio 中创建 LINQ to SQL 项目时，它不会在设计器中创建以下行，大约三周前，它曾经创建过这一行，现在我必须手动执行此操作。然后，如果我在 dbml 文件中进行更改，它会将其删除，并且我必须再次手动添加。巨大的痛苦。这是我所说的几行：

   public DataContext():
                    base(global::System.Configuration.ConfigurationManager.ConnectionString["SiteSqlServer"].ConnectionString, mappingSource)  
        {  
            OnCreated();  
        }

我正在使用 Visual Studio 2008 sp1。

原文

This is an odd one. All the sudden when I create LINQ to SQL projects in Visual Studio would it not create the following line in the designer, up to three weeks ago or so, it used to create this line, now I have to manually do it. Then if I make changes in the dbml file it removes it and I have to manuallhy add again. huge pain. Here is the lines I am speaking of:

   public DataContext():
                    base(global::System.Configuration.ConfigurationManager.ConnectionString["SiteSqlServer"].ConnectionString, mappingSource)  
        {  
            OnCreated();  
        }

I am using Visual Studio 2008 sp1.

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暮凉 2024-08-26 23:30:13

这是一个已知问题。

您必须为数据库上下文实现某种工厂。否则你会一直和设计者纠缠，永远不知道你使用的是哪种连接。

public partial class CustomDataContext {
    public static CustomDataContext Create()
    {
         return new CustomDataContext(ConfigurationManager.ConnectionStrings["CustomConnectionString"].ConnectionString);
    }
}

另一种选择是从 CustomDataContext 继承，并创建一个默认构造函数：

public CustomDataContext : InternalCustomDataContext /* created in designer */
{
 protected string GetCustomConnectionString() {
   return ConfigurationManager.ConnectionStrings["CustomConnectionString"].ConnectionString;
 }
 public CustomDataContext() : base(GetCustomConnectionString())
 {}
}

It's a known problem.

You have to implement sort of factory for DB context. Otherwise you will always stuggle with the designer and never know which connection you are using.

public partial class CustomDataContext {
    public static CustomDataContext Create()
    {
         return new CustomDataContext(ConfigurationManager.ConnectionStrings["CustomConnectionString"].ConnectionString);
    }
}

Another option is inheriting from your CustomDataContext, and creating a default constructor:

public CustomDataContext : InternalCustomDataContext /* created in designer */
{
 protected string GetCustomConnectionString() {
   return ConfigurationManager.ConnectionStrings["CustomConnectionString"].ConnectionString;
 }
 public CustomDataContext() : base(GetCustomConnectionString())
 {}
}

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