得到系统当前的dpi设置值
public class DpiScaleHelper { [DllImport("user32.dll")] static extern IntPtr GetDC(IntPtr ptr); [DllImport("user32.dll", EntryPoint = "ReleaseDC")] public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc); [DllImport("gdi32.dll")] public static extern IntPtr CreateDC( string lpszDriver, // driver name string lpszDevice, // device name string lpszOutput, // not used; should be NULL Int64 lpInitData // optional printer data ); [DllImport("gdi32.dll")] public static extern int GetDeviceCaps( IntPtr hdc, // handle to DC int nIndex // index of capability ); [DllImport("user32.dll")] internal static extern bool SetProcessDPIAware(); const int DRIVERVERSION = 0; const int TECHNOLOGY = 2; const int HORZSIZE = 4; const int VERTSIZE = 6; const int HORZRES = 8; const int VERTRES = 10; const int BITSPIXEL = 12; const int PLANES = 14; const int NUMBRUSHES = 16; const int NUMPENS = 18; const int NUMMARKERS = 20; const int NUMFONTS = 22; const int NUMCOLORS = 24; const int PDEVICESIZE = 26; const int CURVECAPS = 28; const int LINECAPS = 30; const int POLYGONALCAPS = 32; const int TEXTCAPS = 34; const int CLIPCAPS = 36; const int RASTERCAPS = 38; const int ASPECTX = 40; const int ASPECTY = 42; const int ASPECTXY = 44; const int SHADEBLENDCAPS = 45; const int LOGPIXELSX = 88; const int LOGPIXELSY = 90; const int SIZEPALETTE = 104; const int NUMRESERVED = 106; const int COLORRES = 108; const int PHYSICALWIDTH = 110; const int PHYSICALHEIGHT = 111; const int PHYSICALOFFSETX = 112; const int PHYSICALOFFSETY = 113; const int SCALINGFACTORX = 114; const int SCALINGFACTORY = 115; const int VREFRESH = 116; const int DESKTOPVERTRES = 117; const int DESKTOPHORZRES = 118; const int BLTALIGNMENT = 119; private static double m_dipCcale = -1.0; /// <summary> /// 得到dpi的比率 /// </summary> /// <returns></returns> public static double GetDipScale() { if (m_dipCcale == -1.0) { m_dipCcale = 1.0; try { SetProcessDPIAware(); //重要 IntPtr screenDC = GetDC(IntPtr.Zero); int dpi_x = GetDeviceCaps(screenDC, /*DeviceCap.*/LOGPIXELSX); int dpi_y = GetDeviceCaps(screenDC, /*DeviceCap.*/LOGPIXELSY); m_dipCcale = dpi_x / 96.0;//横向系数 = dpi_y / 96.0;//纵向系数 ReleaseDC(IntPtr.Zero, screenDC); } catch (Exception) { //throw; //没有管理员权限就获取不到了 } } return m_dipCcale; }