首先添加引用：using System.Management;

 [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, // 驅動名稱        string lpszDevice, // 設備名稱        string lpszOutput, // 可設置為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 LOGPIXELSX = 88;        const int LOGPIXELSY = 90;
//在方法中添加如下代碼進行獲取
 SetProcessDPIAware(); //這句很重要            IntPtr screenDC = GetDC(IntPtr.Zero);            int dpi_x = GetDeviceCaps(screenDC, LOGPIXELSX);//96 是100%、120 是125%            int dpi_y = GetDeviceCaps(screenDC,LOGPIXELSY);            ReleaseDC(IntPtr.Zero, screenDC);