Question

我正在尝试以编程方式更改PC上的音量但是我没有使用此代码获得任何结果，我在此处（How to programmatically set the system volume?）执行了另一个答案来执行此操作。没有错误，但是当我调用该函数时没有任何反应，任何人都可以帮忙吗？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace UnRestrict.Forms
{

    static class Sounds
    {
        //hexidecimal values for the values needed
        private const int VOLUP = 0xA0000;
        private const int VOLDOWN = 0x90000;
        private const int VOLMUTE = 0x80000;
        private const int APPCMND = 0x319;

        [DllImport("user32.dll")]
        public static extern IntPtr SendMessageW(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        public static void VolumeUp()
        {
            SendMessageW(IntPtr.Zero, APPCMND, IntPtr.Zero, (IntPtr) VOLUP);
        }

        public static void VolumeDown()
        {
            SendMessageW(IntPtr.Zero, APPCMND, IntPtr.Zero, (IntPtr)VOLDOWN);
        }

        public static void VolumeMute()
        {
            SendMessageW(IntPtr.Zero, APPCMND, IntPtr.Zero, (IntPtr)VOLMUTE);
        }

    }
}

Answer 1

我修复了它，我在某个地方读到了这句话，SendMessageW()对hwnd和wParam参数没有任何作用，你可以传递一个空指针(IntPtr.Zero)而没有问题。这是我错的地方。我将IntPtr.Zero值更改为Process.GetCurrentProcess().Handle，现在一切都很好！

奇怪的是，返回的vlaue仍然不是'1'，但我也读到这可能是正常的。

最终守则：

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace UnRestrict.Forms
{

    static class Sounds
    {
        //hexidecimal values for the values needed
        private const int VOLUP = 0xA0000;
        private const int VOLDOWN = 0x90000;
        private const int VOLMUTE = 0x80000;
        private const int APPCMND = 0x319;

        [DllImport("user32.dll")]
        public static extern IntPtr SendMessageW(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        public static void VolumeUp()
        {
            int val = (Int32)SendMessageW(Process.GetCurrentProcess().Handle, APPCMND, Process.GetCurrentProcess().Handle, (IntPtr)VOLUP);
        }

        public static void VolumeDown()
        {
            SendMessageW(Process.GetCurrentProcess().Handle, APPCMND, Process.GetCurrentProcess().Handle, (IntPtr)VOLDOWN);
        }

        public static void VolumeMute()
        {
            SendMessageW(Process.GetCurrentProcess().Handle, APPCMND, Process.GetCurrentProcess().Handle, (IntPtr)VOLMUTE);
        }

    }
}

为什么我不能在代码中更改音量？

1 个答案: