TextBox，RichTextBox设置行高

/// <summary>

        /// 设置行距

        /// </summary>

        /// <param name="ctl">控件</param>

        /// <param name="dyLineSpacing">间距，初始值至少大于(font.size+1)*30</param>

        public static void SetLineHeight(Control ctl, int dyLineSpacing)
        {
            PARAFORMAT2 fmt = new PARAFORMAT2();
            fmt.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(fmt);
            fmt.bLineSpacingRule = 4;// bLineSpacingRule;
            fmt.dyLineSpacing = dyLineSpacing;
            fmt.dwMask = PFM_LINESPACING;
            try
            {
                SendMessage(new System.Runtime.InteropServices.HandleRef(ctl, ctl.Handle), EM_SETPARAFORMAT, 0, ref fmt);
            }
            catch
            {

            }
        }
        public const int WM_USER = 0x0400;
        public const int EM_GETPARAFORMAT = WM_USER + 61;
        public const int EM_SETPARAFORMAT = WM_USER + 71;
        public const long MAX_TAB_STOPS = 32;
        public const uint PFM_LINESPACING = 0x00000100;
        [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
        public struct PARAFORMAT2
        {
            public int cbSize;
            public uint dwMask;
            public short wNumbering;
            public short wReserved;
            public int dxStartIndent;
            public int dxRightIndent;
            public int dxOffset;
            public short wAlignment;
            public short cTabCount;
            [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValArray, SizeConst = 32)]
            public int[] rgxTabs;
            public int dySpaceBefore;
            public int dySpaceAfter;
            public int dyLineSpacing;
            public short sStyle;
            public byte bLineSpacingRule;
            public byte bOutlineLevel;
            public short wShadingWeight;
            public short wShadingStyle;
            public short wNumberingStart;
            public short wNumberingStyle;
            public short wNumberingTab;
            public short wBorderSpace;
            public short wBorderWidth;
            public short wBorders;
        }

        [System.Runtime.InteropServices.DllImport("user32", CharSet = System.Runtime.InteropServices.CharSet.Auto)]
        private static extern IntPtr SendMessage(System.Runtime.InteropServices.HandleRef hWnd, int msg, int wParam, ref PARAFORMAT2 lParam);