Custom control in c# Net winforms for visual studio

We need a custom RichTextBox control. We are developing an structured reporting app for doctors. Our goal is to create a textbox that can be filled with "blocks" of information based in an array of strings from a template. For example title, 3 o 4 medical sentences and dicussion. The appearance should be same as a RichTextBox with bold and italic styles. The user must be able to edit one of the blocks (one of the sentences) and the edited text should be updated in the array. Also the array can me modified in realtime to new values, all blocks will be updated except those ones which were edited by the doctor. A brief summary of controls requirements: - Text Control for Windows Forms c# Net Framework , to use it in Visual Studio project. - Could be a new control or from a derived class (RichTextBox, Textbox, Html renderer....) - No external dependencies allowed. - Should be able to render text from an array of strings ( "BLOCKS" ), some of the blocks will be in BOLD or ITALIC. - The issue: if the doctor changes something in the textbox, the array item must be changed too. Example: item[0]: Report 8th July 2020 item[1]: , about Fruits. item[2]: We had apples, oranges and bananas. item[3]: Also This is a text very long that does not keep in the client's rectangle width and will use multiple lines to be rendered. Te text box should be able to create a text like, multiple BLOCKS of information based on the items: [item[0]] | [item[1]] | [item[2]] | [item[3]] | After be parsed: Report on 8th July 2020, about fruits. We had apples, oranges and bananas. Also this is a text very long that does not keep in the client's rectangle width and will use multiple lines to be rendered. The user must be able to edit blocks inline. If the doctor select and changes "We had apples, oranges and bananas." to "We had watermelons", item[2] should change to "We had watermelons" If doctor delete or change text affecting to multiple blocks, all array items should be updated to the input values.