how to insert text into aspx page maintaining the same format

Greeting,
I have created a database table with  the following fields
codeId int code nvarchar(4000) source nvarchar(50)
The idea is to create an aspx page input form  and be able to copy and past code into a database while maintaining  the same code text format.
List<string> MyList = (List<string>)Session["MyList "]; if(MyList !=null || MyList != "") { // some code }
what I am getting in database is the following >>> List<string> MyList = (List<string>)Session["MyList "]; if(MyList !=null || MyList != ""){//some code }
basically does not maintain the same format or text.  how am I able to copy code via the input form while the code formate maintain the same in database so when I retrieve the code, it shows same format as I inserted it.
thanks for  your help.
Bob