使用 Ninject 上下文绑定时如何检索属性和特性？

Question

我有构造函数

[ReadFromFile(@"C:\SampleData\login.json")]
public AccountController(IReadRepository<LoginMockDataModel> repository, string filePath) : base(repository)
{
}

该属性包含属性 "FilePath".

public string FilePath {get;set;}

我想检索 "FilePath" 的值，在上述情况下为 "C:\SampleData\login.json"。

是否可以使用 Ninject 的 IContext 检索值？

想法是检索属性的值，然后在绑定中使用它，如下所示：

// FileReadRepo contains a constructor with the argument "filePath"
// which will need a string passed to it which I am trying to retrieve
// from the Attribute above
Bind(typeof(IReadRepository<>)).To(typeof(FileReadRepo<>))
.WhenMemberHas<ReadFromFileAttribute>()
.WithConstructorArgument("filePath", CheckAttributePath);

其中 CheckAttributePath 将是委托：

private object CheckAttributePath(IContext arg)
{
    throw new NotImplementedException();
}

我不确定如何获取属性值。

Answer 1

访问 AccountController 的构造函数是通过 IContext.Request.Target.Member 完成的。所以这有效：

private static object CheckAttributePath(IContext context)
{
    var attributes = context.Request.Target.Member
        .GetCustomAttributes(typeof(ReadFromFileAttribute), false);
    return ((ReadFromFileAttribute)attributes[0]).Path;
}

完整的测试代码（使用 xunit 和 FluentAssertions）：

using System;
using Ninject;
using Ninject.Activation;
using Xunit;
using FluentAssertions;

public interface IReadRepository<T>
{
    string FilePath { get; }
}

public class FileReadRepo<T> : IReadRepository<T>
{
    private readonly string filePath;

    public FileReadRepo(string filePath)
    {
        this.filePath = filePath;
    }

    public string FilePath { get { return this.filePath; } }
}

[AttributeUsage(AttributeTargets.Constructor, AllowMultiple = false, Inherited = false)]
public class ReadFromFileAttribute : Attribute
{
    public readonly string Path;

    public ReadFromFileAttribute(string path)
    {
        this.Path = path;
    }
}

public class AccountController
{
    public readonly IReadRepository<string> Repository;

    [ReadFromFile(IntegrationTest.SampleFilePath)]
    public AccountController(IReadRepository<string> repository)
    {
        this.Repository = repository;
    }
}

public class IntegrationTest
{
    public const string SampleFilePath = @"C:\SampleData\login.json";

    [Fact]
    public void Test()
    {
        var kernel = new StandardKernel();

        kernel.Bind(typeof(IReadRepository<>)).To(typeof(FileReadRepo<>))
            .WhenMemberHas<ReadFromFileAttribute>()
            .WithConstructorArgument("filePath", CheckAttributePath);

        kernel.Get<AccountController>().Repository.FilePath.Should().Be(SampleFilePath);
    }

    private static object CheckAttributePath(IContext context)
    {
        var attributes = context.Request.Target.Member.GetCustomAttributes(
            typeof(ReadFromFileAttribute), false);
        return ((ReadFromFileAttribute)attributes[0]).Path;
    }
}

使用 Ninject 上下文绑定时如何检索属性和特性？

How can I retrieve the attribute and the properties when using Ninject contextual binding?

c#

dependency-injection

ninject

contextual-binding