如何在.net core 3.1中使用ConfigurationBulder绑定到配置类

Question

我想使用ConfigurationBuidler读取我的appsettings.json文件。我看不到我在做什么错。

我的文件是

{
  "comment": "this gets copied to bin\\debug on build. the app updates the copy. However to remember the settings you need to paste them here",
  "col1Width": "344"
}

我的测试失败

[TestMethod]
public void TestMethod1()
{
    var configuration = Helper.LoadConfiguration("appsettings.json");
    Assert.IsTrue(configuration.Properties.Keys.Contains("col1Width")); // fails here
}

我的助手班是

public static  class Helper
{
    public static ConfigurationBuilder LoadConfiguration(string filename)
    {
        var configuration = new ConfigurationBuilder();
        var currentDirectory = System.IO.Directory.GetCurrentDirectory();
        configuration.SetBasePath(currentDirectory);
        configuration.AddJsonFile(path: filename, optional: false, reloadOnChange: true);
        configuration.Build();
        return configuration;
    }
}

[更新]

根据马可向我指出的博客文章，我更正了问题标题并更新了代码，如下所示。

仅.Bind不可用

public static  class Helper
{
    public static FeedReadConfiguration GetApplicationConfiguration( )
    {
        var configuration = new FeedReadConfiguration();
        var currentDirectory = System.IO.Directory.GetCurrentDirectory();

        var iConfig = GetIConfigurationRoot(currentDirectory);

        iConfig
            .GetSection("FeedRead")
            .Bind(configuration); // Not available

        return configuration;
    }

    public static IConfigurationRoot GetIConfigurationRoot(string outputPath)
    {
        return new ConfigurationBuilder()
            .SetBasePath(outputPath)
            .AddJsonFile("appsettings.json")
            .Build();
    }

}
public class FeedReadConfiguration
{
    public int Col1Width { get; set; }
}

Answer 1

基于显示的设置文件，没有"FeedRead"部分

需要直接从根目录读取设置。

public static class Helper {
    public static FeedReadConfiguration GetApplicationConfiguration( ) {

        var currentDirectory = System.IO.Directory.GetCurrentDirectory();

        var iConfig = GetIConfigurationRoot(currentDirectory);

        //Microsoft.Extensions.Configuration.Binder.dll
        FeedReadConfiguration configuration = iConfig.Get<FeedReadConfiguration>();

        return configuration;
    }

    public static IConfiguration GetIConfigurationRoot(string outputPath) {
        return new ConfigurationBuilder()
            .SetBasePath(outputPath)
            .AddJsonFile("appsettings.json")
            .Build();
    }    
}

参考Configuration in ASP.NET Core

参考Options pattern in ASP.NET Core