实体框架 - 如何获得种子的方法相对文件路径 [英] Entity Framework - How to get relative file path in seed method

问题描述

为什么是文件路径为空？如何获取相对文件路径任何想法？

Why is filePath null? Any ideas on how to get the relative filePath?

internal sealed class Configuration : DbMigrationsConfiguration<MvcProject.Models.FileDb>
{
    public Configuration()
    {
        // code here is not relevant to question
    }
    protected override void Seed(MvcProject.Models.FileDb context)
    {    
        string filePath = System.Web.HttpContext.Current.Server.MapPath("~/Content/File.txt");

        // read File.txt using filePath and update the database
    }
}

我在Configuration.cs文件上面code在迁移时的实体框架是建立在ASP .NET MVC项目创建的文件夹

I have the above code in Configuration.cs file in Migrations folder created when entity framework is set up on an ASP .NET MVC project

当我运行程序包管理器控制台更新，数据库-Verbose我得到一个错误的文件路径为null。

When I run "Update-Database -Verbose" in Package Manager Console I get an error that filePath is null.

如果我手动设置文件路径以绝对URL到文件中：

If I manually set filePath with an absolute URL to the file:

string filePath = "C:/Users/User1/My Documents/Visual Studio 2012/Projects/MvcProject/Content/File.txt";

一切工作正常。

Everything works fine.

显然，目标是有相对路径，以使对不同的设置不同的开发工作。

Obviously the goal is to have a relative path to enable work with different developers on different setups.

说实话我需要的是文件 - 不一定的路径。任何帮助将AP preciated。

Truth be told all I need is the file - not necessarily the path. Any help will be appreciated.

推荐答案

我用这个功能来种子方法中映射路径，不是很干净，但它的工作原理：

I use this function to map paths inside the Seed method, not very clean but it works:

private string MapPath(string seedFile)
{
    if(HttpContext.Current!=null)
        return HostingEnvironment.MapPath(seedFile);

    var absolutePath = new Uri(Assembly.GetExecutingAssembly().CodeBase).AbsolutePath;
    var directoryName = Path.GetDirectoryName(absolutePath);
    var path = Path.Combine(directoryName, ".." + seedFile.TrimStart('~').Replace('/','\\'));

    return path;
}

然后就使用调用它：

then just call it using:

   using (var streamReader = new StreamReader(MapPath("~/Data/MyFile.csv")))

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