C#

Hello all friends,
I am newbee here right now, i'm trying to solve my problem code but it's doesn't clear.
I want to get value from my string textBox.Text. initial textBox is hmI7Segment1.Text. it's has string Format as "Channel1.DV1.DB1.Level1". i wish to convert double value from this string into textBoxTarget.Text.
so, here is code problem:
hmI7Segment1.Text = "Channel1.DV1.DB1.Level1";
TextBox txtBoxTarget = converted.Format [hmI7Segment1.Text] as TextBox; 
 
if all of you have solution, please help me to solve my case. thanks for all of you are.
 
 
Marbun

/// <summary>
        /// Find the location of a bitmap within another bitmap
        /// </summary>
        /// <param name="bmpNeedle">Image you want to find</param>
        /// <param name="bmpHaystack">Where we want to search for the image</param>
        /// <param name="location">Where we found the image</param>
        /// <returns>if the needle was found sucessfully</returns>
        private bool FindBitmap(Bitmap bmpNeedle, Bitmap bmpHaystack, out Point location, out Point locationA)
        {
            Random rnd = new Random();
            int rndmousex = rnd.Next(-5, 5);
            int rndmousey = rnd.Next(-5, 5);
            for (int outerX = 0; outerX < bmpHaystack.Width - bmpNeedle.Width; outerX++)
            {
                for (int outerY = 0; outerY < bmpHaystack.Height - bmpNeedle.Height; outerY++)
                {
                    for (int innerX = 0; innerX < bmpNeedle.Width; innerX++)
                    {
                        for (int innerY = 0; innerY < bmpNeedle.Height; innerY++)
                        {
                            Color cNeedle = bmpNeedle.GetPixel(innerX, innerY);
                            Color cHaystack = bmpHaystack.GetPixel(innerX + outerX, innerY + outerY);
                            if (cNeedle.R != cHaystack.R || cNeedle.G != cHaystack.G || cNeedle.B != cHaystack.B)
                            {
                                goto notFound;
                            }
                        }
                    }
                    location = new Point(outerX + rndmousex, outerY + rndmousey);
                    locationA = new Point(outerX, outerY);
                    return true;
                notFound:
                    continue;
                }
            }
            location = Point.Empty;
            locationA = Point.Empty;
            return false;
        }

/// <summary>
       /// Takes a snapshot of the screen
       /// </summary>
       /// <returns>screenshot</returns>
       private Bitmap Screenshot()
       {
           Bitmap bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);

           //creates the graphics object to make the bitmap
           Graphics g = Graphics.FromImage(bmpScreenshot);


           g.CopyFromScreen(0, 0, 0, 0, Screen.PrimaryScreen.Bounds.Size);
           return bmpScreenshot;


       }