how to Restrict the Size in Richtextbox to 10 KB

Try below Code Written By Me

   private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            if (ofd.ShowDialog() ==DialogResult.OK)
            {
                String Filename = ofd.FileName.ToString();
               Bitmap bmp = new Bitmap(Filename);
                FileInfo finfo = new FileInfo(Filename);
                long FileSize = finfo.Length;
                MessageBox.Show(FileSize.ToString());


                DataFormats.Format mydataformat = DataFormats.GetFormat(DataFormats.Bitmap);
                Clipboard.SetDataObject(bmp);
                if (richTextBox1.CanPaste(mydataformat))
                {
                    if (FileSize < 10000)
                        richTextBox1.Paste(mydataformat);
                    else
                        MessageBox.Show("File Size Is bigger then Recommended ");
                }
            }


Hope it Will be Helpful to You

Happy Coding   :-)