Unable to paste any text or file into my computer - clipboard error

I use code to capture application text.

When I run the application, I can not copy and paste any text or file into my pc.I know. Why am I getting this error because the clipboard is cleared every second or two, because I saved the code in a loop. I have a big problem for me and my clients, if they use my application in their pc.I, I want to know can we create a new clipboard just for my use of the application, and not for using my desktop clipboard, or can someone provide my solution for my problem The code that I use,

        try
        {
            IEnumerator enumerator;
            MainModule.StrData = "";
            try
            {
                enumerator = this.chkListbox_odin1.CheckedIndices.GetEnumerator();
                IntPtr parentWnd = FindWindow((null), cboWindows.Text);
                IntPtr mdiClientWnd = FindWindowEx(parentWnd, IntPtr.Zero, "MDIClient", "");
                IntPtr marketwatchWnd = FindWindowEx(mdiClientWnd, IntPtr.Zero, null, windowname);
                while (enumerator.MoveNext())
                {
                    object objectValue = enumerator.Current;
                    this.WindowText(marketwatchWnd);
                }
                //    System.Windows.Forms.SendKeys.SendWait("{ESC}");
                //  Application.DoEvents();
            }
            finally
            {

            }
            Clipboard.Clear();
        }
        catch (Exception exception1)
        {
           // MessageBox.Show(exception1.Message);
        }

Here is a picture of my problem

I can copy while I run my application.

But when I try to insert

,

, - .

.