从 C# 控制台应用程序枚举 UWP MIDI API 设备？

Question

我想使用 Windows 10 UWP MIDI API 获取 Windows 10 中安装的 MIDI 设备列表。 This article 显示使用 C# 获取 MIDI 设备及其 ID 列表的示例代码：

using Windows.Devices.Midi;
using Windows.Devices.Enumeration;
...
private async void ListMidiDevices()
{
    // Enumerate Input devices

    var deviceList = DeviceInformation.FindAllAsync(
             MidiInPort.GetDeviceSelector());

    foreach (var deviceInfo in deviceList)
    {
        Console.WriteLine(deviceInfo.Id);
        Console.WriteLine(deviceInfo.Name);
        Console.WriteLine("----------");
    }

    // Output devices are enumerated the same way, but 
    // using MidiOutPort.GetDeviceSelector()
}

我尝试在 Visual Studio Community 2015 "Hello World" 示例程序中插入 ListMidiDevices 的代码。我将代码块放在 Console.WriteLine("Hello World!"); 的位置在 "hello world" 控制台示例中。我在上面的适当位置添加了 "using" 语句。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Devices.Midi;
using Windows.Devices.Enumeration;

namespace ConsoleApplicationHelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {
            // Enumerate Input devices

            var deviceList = await DeviceInformation.FindAllAsync(
                     MidiInPort.GetDeviceSelector());

            foreach (var deviceInfo in deviceList)
            {
                System.Diagnostics.Debug.WriteLine(deviceInfo.Id);
                System.Diagnostics.Debug.WriteLine(deviceInfo.Name);
                System.Diagnostics.Debug.WriteLine("----------");
            }

            // Output devices are enumerated the same way, but 
            // using MidiOutPort.GetDeviceSelector()        }
        }
    }

编辑 - VS 未构建 UWP 类型。我升级到 VS Community 2019，并安装了 ConsoleAppUniversal.vsix。然后我可以创建一个新项目 - Console App C# Universal:

using System;
using Windows.Devices.Midi;
using Windows.Devices.Enumeration;

// This example code shows how you could implement the required main function for a 
// Console UWP Application. You can replace all the code inside Main with your own custom code.

// You should also change the Alias value in the AppExecutionAlias Extension in the 
// Package.appxmanifest to a value that you define. To edit this file manually, right-click
// it in Solution Explorer and select View Code, or open it with the XML Editor.

namespace ConsoleAppCsharpUniversal
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length == 0)
            {
                Console.WriteLine("starting - no args");

                // Enumerate Input devices

                var deviceList =  DeviceInformation.FindAllAsync(
                         MidiInPort.GetDeviceSelector());

                foreach (var deviceInfo in deviceList)
                {
                    Console.WriteLine(deviceInfo.Id);
                    Console.WriteLine(deviceInfo.Name);
                    Console.WriteLine("----------");
                }
                Console.WriteLine("finish - no args");


            }
            else
            {
                for (int i = 0; i < args.Length; i++)
                {
                    Console.WriteLine($"arg[{i}] = {args[i]}");
                }
            }
            Console.WriteLine("Press a key to continue: ");
            Console.ReadLine();
        }
    }
}

现在唯一剩下的错误是"foreach statement cannot operate on variables of type IAsyncOperation<DeviceInformationCollection> because IAsyncOperation<DeviceInformationCollection> does not contain a public instance definition for GetEnumerator"

是否有另一种不使用异步方法访问设备信息的方法？

Answer 1

您必须确保您的项目至少以 C# 7.1 为目标（我认为该模板在 VS 2019 中确实具有开箱即用的功能）并使用 async Main method feature:

您的方法签名将更改为：

public static async Task Main(string[] args)
{
   ...
}

然后你需要等待FindAllAsync方法：

var deviceList = await DeviceInformation.FindAllAsync(
                         MidiInPort.GetDeviceSelector());

注意： 您可以通过在文本编辑器中打开 csproj 文件并将以下内容添加到 <PropertyGroup> 中来更改 C# 版本：

<LangVersion>7.1</LangVersion>

甚至（如果您想要最新功能）：

<LangVersion>latest</LangVersion>

从 C# 控制台应用程序枚举 UWP MIDI API 设备？

Enumerate UWP MIDI API devices from C# console application?

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