TextModel.cs | Javaв„ў EE 5 Tutorial, The (3rd Edition)

One of my technical editors commented, upon seeing this code, that he likes to arrange his using statements in order of increasing length. That good idea notwithstanding, I suspect that alphabetical might be better. Random is probably worst, and I can t honestly promise that you won t see that here before we re done.

This same individual also rudely pointed out the internal variable lineNr used in this method, asking if it was so much better than lineNumber. It s a good point. I plead a leftover brain cell from back when variables could only be six characters long. Inside a method, you ll often feel a need to trade off the time to type a name with its ability to communicate. When I become aware of the tradeoff , I always try to favor communication: I ll type it only once, but I might read it many times. Unfortunately, I don t always notice.

 using System; 
 using System.Collections; 
 using System.Text; 
 using System.Text.RegularExpressions; 
 namespace Notepad { 
 class TextModel { 
 private ArrayList lines; 
 private int selectionStart; 
 public TextModel() { 
 lines = new ArrayList(); 
 }     private int LineContainingCursor() { 
 int length = 0; 
 int lineNr = 0; 
 int cr = Environment.NewLine.Length; 
 foreach ( String s in lines) { 
 if (length <= selectionStart 
 && selectionStart < length+s.Length + cr ) 
 break; 
 length += s.Length + cr; 
 lineNr++; 
 } 
 return lineNr; 
 } 
 public void Enter() { 
 InsertParagraphTag(); 
 } 
 public void InsertParagraphTag() { 
 // 
 // On Enter, we change the TextModel lines to insert, after the line 
 // containing the cursor, a blank line, and a line with <P></P>. 
 // We set the new cursor 
 // location to be between the P tags: <P></P>. 
 // 
 // handle empty array special case (yucch) 
 if ( lines.Count == 0 ) { 
 lines.Add( "<P></P>" ); 
 selectionStart = 3; 
 return; 
 } 
 lines.InsertRange(LineContainingCursor()+1, NewParagraph()); 
 // set cursor location 
 selectionStart = NewSelectionStart(LineContainingCursor() + 2); 
 } 
 private int NewSelectionStart(int cursorLine) { 
 int length = 0; 
 for (int i = 0; i < cursorLine; i++) 
 length += ((String)lines[i]).Length + Environment.NewLine.Length; 
 return length + "<p>".Length; 
 } 
 public ArrayList NewParagraph() { 
 ArrayList temp = new ArrayList(); 
 temp.Add(""); 
 temp.Add("<P></P>"); 
 return temp; 
 } 
 public ArrayList Lines { 
 get { 
 return lines; 
 } 
 set { 
 lines = value; 
 }     } 
 public void SetLines(String[] lines) { 
 this.Lines = new ArrayList(lines); 
 } 
 public String[] LinesArray() { 
 String[] result = new String[lines.Count]; 
 lines.CopyTo(result); 
 return result; 
 } 
 public String TestText { 
 get { 
 StringBuilder b = new StringBuilder(); 
 foreach(String s in lines) { 
 b.Append(s); 
 b.Append(System.Environment.NewLine); 
 } 
 b.Insert(SelectionStart,""); 
 return b.ToString(); 
 } 
 } 
 public int SelectionStart { 
 get { 
 return selectionStart; 
 } 
 set { 
 selectionStart = value; 
 } 
 } 
 public void ChangeToH2() { 
 ArrayList linesList = Lines; 
 String oldLine = (String) linesList[LineContainingCursor()]; 
 Regex r = new Regex("<(?<prefix>.*)>(?<body>.*)</(?<suffix>.*)>"); 
 Match m = r.Match(oldLine); 
 String newLine = "<H2>" + m.Groups["body"] + "</H2>"; 
 linesList[LineContainingCursor()] = newLine; 
 Lines = linesList; 
 } 
 } 
 }