#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <iostream>
#include <Ntddvdeo.h>
using namespace std;
#define IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS CTL_CODE(FILE_DEVICE_VIDEO, 0x125, METHOD_BUFFERED, FILE_ANY_ACCESS)
#define IOCTL_VIDEO_QUERY_DISPLAY_BRIGHTNESS CTL_CODE(FILE_DEVICE_VIDEO, 0x126, METHOD_BUFFERED, FILE_ANY_ACCESS)
#define IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS CTL_CODE(FILE_DEVICE_VIDEO, 0x127, METHOD_BUFFERED, FILE_ANY_ACCESS)
int setBrightness(int level)
{
HANDLE h;
DWORD nOutBufferSize = 256;
BYTE SupportedBrightness[256];
DWORD g_supportedLevelCount;
DISPLAY_BRIGHTNESS DisplayBrightness;
memset(SupportedBrightness, 0, sizeof(SupportedBrightness));
/* use createfile function to open lcd.
* url from microsoft about IOCTL code.
* http://msdn.microsoft.com/en-us/library/windows/desktop/aa372703%28v=vs.85%29.aspx
*/
/*
* char* 和 wchar_t* 互相转换参考博客
* https://www.cnblogs.com/icqw/p/4614877.html
*/
/*
* c++代码参考博客
* https://blog.csdn.net/weixin_34111819/article/details/86328019
*/
char temchar[] = "\\\\.\\LCD";
char* szSour = temchar;
WCHAR Temp[128] = { 0 };
mbstowcs(Temp, szSour, strlen(szSour));
h = CreateFile(Temp, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, 0);
if (h == INVALID_HANDLE_VALUE) {
printf("Open \\\\.\\LCD error");
exit(1);
}
/* Query for display supported level */
if (!DeviceIoControl(h, IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS, NULL, 0, SupportedBrightness, nOutBufferSize, &g_supportedLevelCount, NULL)) {
printf("IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS error - %d, - buffer: %d ", g_supportedLevelCount, nOutBufferSize);
exit(1);
}
if (g_supportedLevelCount == 0) /* 0 means not supported */
{
printf("\nLCD not support LEVEL COUNT", g_supportedLevelCount);
exit(1);
}
DisplayBrightness.ucDisplayPolicy = 0;
DisplayBrightness.ucACBrightness = level;
DisplayBrightness.ucDCBrightness = level;
/* Set display backlight level */
nOutBufferSize = sizeof(DisplayBrightness);
if (!DeviceIoControl(h, IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS, (DISPLAY_BRIGHTNESS*)&DisplayBrightness, nOutBufferSize, NULL, 0, &nOutBufferSize, NULL)) {
printf("IOCTL_VIDEO_SET_SUPPORTED_BRIGHTNESS error - %d, - buffer: %d ", g_supportedLevelCount, nOutBufferSize);
exit(1);
}
Sleep(500); /* delay for some time while wmi event changed */
nOutBufferSize = sizeof(DisplayBrightness);
if (!DeviceIoControl(h, IOCTL_VIDEO_QUERY_DISPLAY_BRIGHTNESS, NULL, 0, (DISPLAY_BRIGHTNESS*)&DisplayBrightness, nOutBufferSize, &nOutBufferSize, NULL)) {
printf("IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS error - %d, - buffer: %d ", g_supportedLevelCount, nOutBufferSize);
exit(1);
}
printf("\nBrightness_AC: %d\nBrightness_DC: %d", DisplayBrightness.ucACBrightness, DisplayBrightness.ucDCBrightness);
}
int main(int argc, char* argv[]) {
///* program with arguments support */
//if (argc == 3 && strcmp("-b", argv[1]) == 0) {
// setBrightness(atoi(argv[2]));
//}
//else {
// help();
//}
int a;
cin >> a;
setBrightness(a);
return 0;
}
编译环境是VS,众所周知VS对代码的要求相对严格。所以这位大佬的代码有些部分需要修改。在这里我会指出修改地方以及对修改的部分进行解释。
首先#include <Ntddvdeo.h>直接引用就可以了不要加前缀,VS会自动寻找这个头文件的。
char temchar[] = "\\\\.\\LCD";
char* szSour = temchar;
WCHAR Temp[128] = { 0 };
mbstowcs(Temp, szSour, strlen(szSour));
h = CreateFile(Temp, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, 0);
其次这里的Temp参数,之前大佬的写法是直接“\\\\.\\LCD”,但是这个参数的位置是填到一个WCHAR类型的参数,所以我们要对其进行转换。在转换的过程中VS不允许使用char*指针指向一个字符串常量,所以我们要先将这个字符串常量赋值给一个字符数组,然后再用指针指向它就行了。转换的方法在另一位大佬的博客中,我在代码中已经作为注释给出地址了(感谢各个前辈们做出的贡献)。
最后我要注明一下,这个int setBrightness(int level)中的level的范围是0到100,虽然大多数情况下调到0也能看清,但是万一呢是吧,最好测试的时候别调到零。
上面的是c++代码现在让我们来做成c#模块。(这个模块文末我会放出连接,有百度云和CSDN两个连接,还有gitHub有全部的源代码)我们的思路是将C++编译成DLL模块,然后由c#引用,并在C#中封装成模块的方式来供C#调用。
下面是c++封装DLL的教程(正在准备材料,还没写完,先存着)