Protect the first words in the text box, but allow adding / editing text behind these words

Question

So, I have a text box in C # (using .NET forms) where I am going to accept a user string for some input.

This line already has text (arguments) at the beginning, which will exist at the beginning of the line no matter what. He must be there. I want them to know about this, but not be able to delete the words from the text field (so they don’t think that they deleted it already when it will be there anyway)

Therefore, these first arguments cannot be deleted or edited.

Any text after these arguments can be added or changed freely, as usual.

Is this possible in C #?

Answer 1

WinForms, RichTextBox. Multiline=False, :

richTextBox1.Text = "LOCKED";
richTextBox1.SelectAll();
richTextBox1.SelectionProtected = true;

, "LOCKED", :

richTextBox1.Text = "LOCKED information";
richTextBox1.Select(0, 6);
richTextBox1.SelectionProtected = true;