ASCII read and write

Hi

I have a Program that reads a charactor from a text box and replaces a specific byte in a hex file. when the text box is empty the specific byte needs to be 0x20 but for somreason I can't get that to work.

                stream.Position = 0x118d5;
                byte[] LogoDataBy0 = { 0x00 };
                if (string.IsNullOrWhiteSpace(textBox12.Text))
                {
                    LogoDataBy0[0] = 0x20;
                }
                else
                {
                    LogoDataBy0 = ASCIIEncoding.ASCII.GetBytes(textBox12.Text);
                }
                stream.WriteByte(LogoDataBy0[0]);

This works for the empty textbox but for some reason now won't write the charactor if I fill the Textbox.

Any help would be greatly appreciated.

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