WPF 應用程序沒有輸出到控制台？ (No output to console from a WPF application?)

問題描述

WPF 應用程序沒有輸出到控制台？ (No output to console from a WPF application?)

我在一個非常簡單的 WPF 測試應用程序中使用 Console.WriteLine()，但是當我從命令行執行該應用程序時，我沒有看到任何內容被寫入控制台。有誰知道這裡會發生什麼？

我可以通過在 VS 2008 中創建一個 WPF 應用程序來重現它，並在任何地方簡單地添加 Console.WriteLine("text")它被執行的地方。有什麼想法嗎？

我現在只需要像 Console.WriteLine() 這樣簡單的東西。我意識到我可以使用 log4net 或其他一些日誌記錄解決方案，但我真的不需要這個應用程序的那麼多功能。

編輯： 我應該記得 Console.WriteLine() 用於控制台應用程序。哦，好吧，沒有愚蠢的問題，對吧？:‑) 我現在只使用 System.Diagnostics.Trace.WriteLine() 和 DebugView。

參考解法

方法 1:

You can use

Trace.WriteLine("text");

This will output to the "Output" window in Visual Studio (when debugging).

make sure to have the Diagnostics assembly included:

using System.Diagnostics;

方法 2:

Right click on the project, "Properties", "Application" tab, change "Output Type" to "Console Application", and then it will also have a console.

方法 3:

You'll have to create a Console window manually before you actually call any Console.Write methods. That will init the Console to work properly without changing the project type (which for WPF application won't work).

Here's a complete source code example, of how a ConsoleManager class might look like, and how it can be used to enable/disable the Console, independently of the project type.

With the following class, you just need to write ConsoleManager.Show() somewhere before any call to Console.Write...

[SuppressUnmanagedCodeSecurity]
public static class ConsoleManager
{
    private const string Kernel32_DllName = "kernel32.dll";

    [DllImport(Kernel32_DllName)]
    private static extern bool AllocConsole();

    [DllImport(Kernel32_DllName)]
    private static extern bool FreeConsole();

    [DllImport(Kernel32_DllName)]
    private static extern IntPtr GetConsoleWindow();

    [DllImport(Kernel32_DllName)]
    private static extern int GetConsoleOutputCP();

    public static bool HasConsole
    {
        get { return GetConsoleWindow() != IntPtr.Zero; }
    }

    /// <summary>
    /// Creates a new console instance if the process is not attached to a console already.
    /// </summary>
    public static void Show()
    {
        //#if DEBUG
        if (!HasConsole)
        {
            AllocConsole();
            InvalidateOutAndError();
        }
        //#endif
    }

    /// <summary>
    /// If the process has a console attached to it, it will be detached and no longer visible. Writing to the System.Console is still possible, but no output will be shown.
    /// </summary>
    public static void Hide()
    {
        //#if DEBUG
        if (HasConsole)
        {
            SetOutAndErrorNull();
            FreeConsole();
        }
        //#endif
    }

    public static void Toggle()
    {
        if (HasConsole)
        {
            Hide();
        }
        else
        {
            Show();
        }
    }

    static void InvalidateOutAndError()
    {
        Type type = typeof(System.Console);

        System.Reflection.FieldInfo _out = type.GetField("_out",
            System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);

        System.Reflection.FieldInfo _error = type.GetField("_error",
            System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);

        System.Reflection.MethodInfo _InitializeStdOutError = type.GetMethod("InitializeStdOutError",
            System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);

        Debug.Assert(_out != null);
        Debug.Assert(_error != null);

        Debug.Assert(_InitializeStdOutError != null);

        _out.SetValue(null, null);
        _error.SetValue(null, null);

        _InitializeStdOutError.Invoke(null, new object[] { true });
    }

    static void SetOutAndErrorNull()
    {
        Console.SetOut(TextWriter.Null);
        Console.SetError(TextWriter.Null);
    }
} 

方法 4:

Old post, but I ran into this so if you're trying to output something to Output in a WPF project in Visual Studio, the contemporary method is:

Include this:

using System.Diagnostics;

And then:

Debug.WriteLine("something");

方法 5:

Although John Leidegren keeps shooting down the idea, Brian is correct. I've just got it working in Visual Studio.

To be clear a WPF application does not create a Console window by default.

You have to create a WPF Application and then change the OutputType to "Console Application". When you run the project you will see a console window with your WPF window in front of it.

It doesn't look very pretty, but I found it helpful as I wanted my app to be run from the command line with feedback in there, and then for certain command options I would display the WPF window.

(by Rob、Phobis、Brian、John Leidegren、Smitty、antidemon)

參考文件

1. No output to console from a WPF application? (CC BY‑SA 2.5/3.0/4.0)