Now having gone through the basics, let’s put this to work.

• Create a new windows form project “RedWaveTest” in c#Add the TxTextControl to the project
• Add two buttons: “Mark All” and “Unmark All”
• Double click both the buttons to add event handler (this is required at this stage as when we change the textControl1 declaration, it will not be possible to open the designer.
• Create a class MyTextControl inherited from TxTextControl.TextControl.
• Open the MyTextControl.cs file add following:

• [DllImport("user32", CharSet = CharSet.Auto, SetLastError = true)]
  private static extern int SendMessage(HandleRef hWnd, int msg, int  
                                        wParam, ref IntPtr lParam);
  
  //declaration for formatting constants
  private const int FA_UL_REDZIGZAG = 0x00010000,
                    FA_UL_NOREDZIGZAG = 0x00020000;
  
  //Txt Control Message
  private const int TX_SETFONTATTR = 0x482;
  
  Note: Do not forget to include the System.Runtime.InteropServices namespace.