using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;//必须引用此项

//警告：实验此代码可能给你的显示器的显示带来问题 ，花了两个小时查API的用法
// 不过我试过是没有事情的（BS下自己：不是用自己的机子）

namespace WindowsApplication1
...{
public partial class Form1 : Form
...{

public Form1()
...{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
...{
SetGamma(trackBar1.Value);
}
[DllImport("gdi32.dll")]
public static extern int GetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp);
RAMP ramp = new RAMP();

[DllImport("gdi32.dll")]
public static extern int SetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp);

[DllImport("user32.dll")]
static extern IntPtr GetDC(IntPtr hWnd);

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct RAMP
...{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Red;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Green;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)]
public UInt16[] Blue;
}
void SetGamma(int gamma)
...{
ramp.Red = new ushort[256];
ramp.Green = new ushort[256];
ramp.Blue = new ushort[256];

for (int i = 1; i < 256; i++)
...{
// gamma 必须在3和44之间
ramp.Red[i] = ramp.Green[i] = ramp.Blue[i] = (ushort)(Math.Min(65535, Math.Max(0, Math.Pow((i + 1) / 256.0, gamma * 0.1) * 65535 + 0.5)));
}
SetDeviceGammaRamp(GetDC(IntPtr.Zero), ref ramp);
}