how to change HyperLink style and textColor into richtextbox c# winform

public class RichTextBoxEx : RichTextBox
    {
        #region Interop-Defines
        [StructLayout(LayoutKind.Sequential)]
        private struct CHARFORMAT2_STRUCT
        {
            public UInt32 cbSize;
            public UInt32 dwMask;
            public UInt32 dwEffects;
            public Int32 yHeight;
            public Int32 yOffset;
            public Int32 crTextColor; //--------------
            public byte bCharSet;
            public byte bPitchAndFamily;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
            public char[] szFaceName;
            public UInt16 wWeight;
            public UInt16 sSpacing;
            public int crBackColor; // Color.ToArgb() -> int


            public int lcid;
            public int dwReserved;
            public Int16 sStyle;
            public Int16 wKerning;
            public byte bUnderlineType; //UnderLine
            public byte bAnimation;
            public byte bRevAuthor;
            public byte bReserved1;
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);


        private const int WM_USER = 0x400;
        private const int EM_GETCHARFORMAT = WM_USER + 58;
        private const int EM_SETCHARFORMAT = WM_USER + 68;


        private const int SCF_SELECTION = 0x0001;
        private const int SCF_WORD = 0x0002;
        private const int SCF_ALL = 0x0004;

        #region CHARFORMAT2 Flags


        private const UInt32 CFE_BOLD = 0x0001;
        private const UInt32 CFE_ITALIC = 0x0002;
        private const UInt32 CFE_UNDERLINE = 0x0004; //UnderLine


        private const UInt32 CFE_STRIKEOUT = 0x0008;
        private const UInt32 CFE_PROTECTED = 0x0010;
        private const UInt32 CFE_LINK = 0x0020;
        private const UInt32 CFE_AUTOCOLOR = 0x40000000;
        private const UInt32 CFE_SUBSCRIPT = 0x00010000;        /* Superscript and subscript are */
        private const UInt32 CFE_SUPERSCRIPT = 0x00020000;      /*  mutually exclusive			 */

        private const int CFM_SMALLCAPS = 0x0040;           /* (*)	*/
        private const int CFM_ALLCAPS = 0x0080;         /* Displayed by 3.0	*/
        private const int CFM_HIDDEN = 0x0100;          /* Hidden by 3.0 */
        private const int CFM_OUTLINE = 0x0200;         /* (*)	*/
        private const int CFM_SHADOW = 0x0400;          /* (*)	*/
        private const int CFM_EMBOSS = 0x0800;          /* (*)	*/
        private const int CFM_IMPRINT = 0x1000;         /* (*)	*/
        private const int CFM_DISABLED = 0x2000;
        private const int CFM_REVISED = 0x4000;

        private const int CFM_BACKCOLOR = 0x04000000;
        private const int CFM_LCID = 0x02000000;
        private const int CFM_UNDERLINETYPE = 0x00800000;   //UnderLine	/* Many displayed by 3.0 */


        private const int CFM_WEIGHT = 0x00400000;
        private const int CFM_SPACING = 0x00200000;     /* Displayed by 3.0	*/
        private const int CFM_KERNING = 0x00100000;     /* (*)	*/
        private const int CFM_STYLE = 0x00080000;       /* (*)	*/
        private const int CFM_ANIMATION = 0x00040000;       /* (*)	*/
        private const int CFM_REVAUTHOR = 0x00008000;


        private const UInt32 CFM_BOLD = 0x00000001;
        private const UInt32 CFM_ITALIC = 0x00000002;
        private const UInt32 CFM_UNDERLINE = 0x00000000; // UnderLine

        private const UInt32 CFM_STRIKEOUT = 0x00000008;
        private const UInt32 CFM_PROTECTED = 0x00000010;
        private const UInt32 CFM_LINK = 0x00000020;
        private const UInt32 CFM_SIZE = 0x80000000;
        private const UInt32 CFM_COLOR = 0x40000000;
        private const UInt32 CFM_FACE = 0x20000000;
        private const UInt32 CFM_OFFSET = 0x10000000;
        private const UInt32 CFM_CHARSET = 0x08000000;
        private const UInt32 CFM_SUBSCRIPT = CFE_SUBSCRIPT | CFE_SUPERSCRIPT;
        private const UInt32 CFM_SUPERSCRIPT = CFM_SUBSCRIPT;

        private const byte CFU_UNDERLINENONE = 0x00000000;
        private const byte CFU_UNDERLINE = 0x00000001;
        private const byte CFU_UNDERLINEWORD = 0x00000002; /* (*) displayed as ordinary underline	*/
        private const byte CFU_UNDERLINEDOUBLE = 0x00000003; /* (*) displayed as ordinary underline	*/
        private const byte CFU_UNDERLINEDOTTED = 0x00000004;
        private const byte CFU_UNDERLINEDASH = 0x00000005;
        private const byte CFU_UNDERLINEDASHDOT = 0x00000006;
        private const byte CFU_UNDERLINEDASHDOTDOT = 0x00000007;
        private const byte CFU_UNDERLINEWAVE = 0x00000008;
        private const byte CFU_UNDERLINETHICK = 0x00000009;
        private const byte CFU_UNDERLINEHAIRLINE = 0x0000000A; /* (*) displayed as ordinary underline	*/

public RichTextBoxEx()
        {
            this.DetectUrls = false;
        }

        [DefaultValue(false)]
        public new bool DetectUrls
        {
            get { return base.DetectUrls; }
            set { base.DetectUrls = value; }
        }
public void SetSelectionLink(bool link)
        {
            SetSelectionStyle(CFM_LINK, CFE_LINK, CFU_UNDERLINENONE, CFM_COLOR);
        }

private void SetSelectionStyle(UInt32 mask, UInt32 effect, byte underline, UInt32 crBackColor)
        {
            CHARFORMAT2_STRUCT cf = new CHARFORMAT2_STRUCT();
            cf.cbSize = (UInt32)Marshal.SizeOf(cf);
            cf.dwMask = mask;
            cf.dwEffects = effect;
            cf.bUnderlineType = underline;
            cf.crTextColor = (int)crBackColor;
            cf.crTextColor = ColorTranslator.ToWin32(Color.Red);

            IntPtr wpar = new IntPtr(SCF_SELECTION);
            IntPtr lpar = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf));
            Marshal.StructureToPtr(cf, lpar, true);

            SendMessage(Handle, EM_SETCHARFORMAT, wpar, lpar);

            Marshal.FreeCoTaskMem(lpar);
        }
public void InsertLink(string text, string hyperlink, int position)
        {
            if (position < 0 || position > Text.Length)
            {
                throw new ArgumentOutOfRangeException("position");
            }

            text = ConvertToRtf(text);
            hyperlink = ConvertToRtf(hyperlink);

            SelectionStart = position;
            SelectedRtf = @"{\rtf1\ansi " + text + @"\v #" + hyperlink + @"\v0}";
            Select(position, text.Length + hyperlink.Length + 1);
            SetSelectionLink(true);
            this.SelectionFont = new Font("Microsoft YaHei UI", 9, FontStyle.Bold);
        }
        
}

richTextBox.InsertLink("Google" , "HyperLink text");