C＃ 获取DPI和真实分辨率的方式（可以解决一直是96的问题）

C# 获取DPI和真实分辨率的方式（可以解决一直是96的问题）

                [DllImport("user32.dll")]
                 static extern IntPtr GetDC(IntPtr ptr);
                [DllImport("gdi32.dll")]
                 static extern int GetDeviceCaps(
                IntPtr hdc, // handle to DC
                int nIndex // index of capability
                );
                [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
                 static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);
                const int HORZRES = 8;
                const int VERTRES = 10;
                const int LOGPIXELSX = 88;
                const int LOGPIXELSY = 90;
                const int DESKTOPVERTRES = 117;
                const int DESKTOPHORZRES = 118;
      
             /// <summary>
            /// 获取屏幕分辨率当前物理大小
            /// </summary>
            public static Size WorkingArea
            {
                 get {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    Size size = new Size();
                    size.Width = GetDeviceCaps(hdc, HORZRES);
                    size.Height = GetDeviceCaps(hdc, VERTRES);
                    ReleaseDC(IntPtr.Zero, hdc);
                    return size;    
                }
           }
           /// <summary>
           /// 当前系统DPI_X 大小 一般为96
           /// </summary>
            public static int DpiX
            {
                get
                {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    int DpiX = GetDeviceCaps(hdc, LOGPIXELSX );
                    ReleaseDC(IntPtr.Zero, hdc);
                    return DpiX;
                }
            }
            /// <summary>
            /// 当前系统DPI_Y 大小 一般为96
            /// </summary>
            public static int DpiY
            {
                get
                {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    int DpiX = GetDeviceCaps(hdc,LOGPIXELSY);
                    ReleaseDC(IntPtr.Zero, hdc);
                    return DpiX;
                }
            }
            /// <summary>
            /// 获取真实设置的桌面分辨率大小
            /// </summary>
            public static Size DESKTOP
            {
                get
                {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    Size size = new Size();
                    size.Width = GetDeviceCaps(hdc,DESKTOPHORZRES );
                    size.Height = GetDeviceCaps(hdc, DESKTOPVERTRES);
                    ReleaseDC(IntPtr.Zero, hdc);
                    return size;    
                }
            }
 
            /// <summary>
            /// 获取宽度缩放百分比 （**当获取的DPI的值一直是96的时候，可以通过用此方法获取的值转化为DPI，ScaleX * 96**）
            /// </summary>
            public static float ScaleX
            {
                get
                {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    int t = GetDeviceCaps(hdc, DESKTOPHORZRES);
                    int d = GetDeviceCaps(hdc, HORZRES);
                    float ScaleX = (float)GetDeviceCaps(hdc, DESKTOPHORZRES) / (float)GetDeviceCaps(hdc, HORZRES); 
                    ReleaseDC(IntPtr.Zero, hdc);
                    return ScaleX;
                }
            }
            /// <summary>
            /// 获取高度缩放百分比
            /// </summary>
            public static float ScaleY
            {
                get
                {
                    IntPtr hdc = GetDC(IntPtr.Zero);
                    float ScaleY = (float)(float)GetDeviceCaps(hdc, DESKTOPVERTRES) / (float)GetDeviceCaps(hdc, VERTRES);
                    ReleaseDC(IntPtr.Zero, hdc);
                    return ScaleY;
                }
            }
       #endregion

转自https://blog.csdn.net/htiannuo/article/details/77086550