implemented change of color in MultiFormatTextBox

MultiTerm.Wpf.CustomControl/MultiFormatTextBox/MultiFormatTextBox.cs

@@ -1,9 +1,11 @@
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Documents;
 using System.Windows.Input;
 using System.Windows.Media;
 
@@ -49,6 +51,14 @@ internal class Format
         this.BackgroundBrush = backgroundBrush;
         this.IsKeyValid = keyValidator;
     }
+    public Format(string name, string backgroundBrushColorHexCode, Predicate<Key> keyValidator)
+    {
+        this.Name = name;
+        var brushObj = new BrushConverter().ConvertFrom(backgroundBrushColorHexCode);
+        if(brushObj == null) throw new ArgumentException(nameof(backgroundBrushColorHexCode));
+        this.BackgroundBrush = (SolidColorBrush)brushObj;
+        this.IsKeyValid = keyValidator;
+    }
     public static List<string> GetListOfNames(IEnumerable<Format> formats)
     {
         return formats.Select(item => item.Name).ToList();
@@ -57,19 +67,24 @@ internal class Format
 
 public class MultiFormatTextBox : Control
 {
+    private static readonly Brush defaultBackgroundBrush = Brushes.White;
     private static readonly List<Format> formats = new()
     {
-        // character input, accepts all keys
-        new Format("CHAR", Brushes.White, delegate(Key k) { return true; }),
+        // character input, accepts all keys except space
+        new Format("CHAR", Brushes.LightSkyBlue, delegate(Key k) { return (k != Key.Space); }),
+        //new Format("CHAR", "B4EBEB", delegate(Key k) { return (k != Key.Space); }),
         // hex input, ignores all keys that are not inbetween 0 and F
-        new Format("HEX", Brushes.Orange, delegate(Key k) { return (k >= Key.D0 && k <= Key.F); }),
+        new Format("HEX", Brushes.LightGreen, delegate(Key k) { return (k >= Key.D0 && k <= Key.F); }),
+        //new Format("HEX", "C8C8FF", delegate(Key k) { return (k >= Key.D0 && k <= Key.F); }),
         // binary input, ignores all keys except 0 and 1
-        new Format("BIN", Brushes.AliceBlue, delegate(Key k) { return (k == Key.D0 || k == Key.D1); })
+        new Format("BIN", Brushes.LightPink, delegate(Key k) { return (k == Key.D0 || k == Key.D1); })
+        //new Format("BIN", "C8FFC8", delegate(Key k) { return (k == Key.D0 || k == Key.D1); })
     };
 
     private ComboBox comboBox;
     private RichTextBox richTextBox;
     private Format currentlySelectedFormat = formats.First();
+    private int offsetContentStartToFormatStart;
 
     static MultiFormatTextBox()
     {
@@ -96,10 +111,13 @@ public class MultiFormatTextBox : Control
         {
             this.richTextBox = richTextBox;
             this.richTextBox.KeyDown += RichTextBox_KeyDown;
+            this.richTextBox.TextChanged += RichTextBox_TextChanged;
+            this.offsetContentStartToFormatStart = 0;
         }
 
     }
 
+
     private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
     {
         // match all formats with the name selected in the combobox
@@ -109,14 +127,47 @@ public class MultiFormatTextBox : Control
         {
             throw new Exception($"{nameof(ComboBox_SelectionChanged)} could not match a correct amount of formats");
         }
-        // set currently selected format
+        // set currently selected format, reset offset counter
         this.currentlySelectedFormat = matchingFormats.First();
+
+        // insert space to separate formats
+        this.InsertSeparation();
+
+        // set new start position
+        this.offsetContentStartToFormatStart = this.richTextBox.CaretPosition.GetOffsetToPosition(this.richTextBox.Document.ContentStart);
+
+        // focus textbox
+        this.richTextBox.Focus();
+    }
+
+    private void InsertSeparation()
+    {
+        // disable event handler
+        this.richTextBox.TextChanged -= RichTextBox_TextChanged;
+
+        // store caret position before
+        this.offsetContentStartToFormatStart = this.richTextBox.CaretPosition.GetOffsetToPosition(this.richTextBox.Document.ContentStart);
+
+        // insert
+        this.richTextBox.AppendText(" ");
+
+        // change background
+        RtbChangeTextBackground(this.richTextBox,
+           start: this.richTextBox.Document.ContentStart.GetPositionAtOffset(-this.offsetContentStartToFormatStart),
+           end: this.richTextBox.Document.ContentEnd,
+           color: defaultBackgroundBrush);
+
+        // store new caret position after
+        this.offsetContentStartToFormatStart = this.richTextBox.CaretPosition.GetOffsetToPosition(this.richTextBox.Document.ContentStart);
+
+        // reenable
+        this.richTextBox.TextChanged += RichTextBox_TextChanged;
     }
 
     private void RichTextBox_KeyDown(object sender, KeyEventArgs e)
     {
         // guard combobox null
-        if (comboBox == null) throw new Exception($"{nameof(comboBox)} cannot be null");
+        if (this.comboBox == null) throw new Exception($"{nameof(this.comboBox)} cannot be null");
 
         // if key is invalid for this format => ignore it (handled = true)
         if(this.currentlySelectedFormat.IsKeyValid(e.Key) == false)
@@ -124,4 +175,28 @@ public class MultiFormatTextBox : Control
             e.Handled = true;
         }
     }
+
+    private void RichTextBox_TextChanged(object sender, TextChangedEventArgs e)
+    {
+        if(e.Changes.Count > 1) { return; }
+
+        RtbChangeTextBackground(this.richTextBox,
+            start: this.richTextBox.Document.ContentStart.GetPositionAtOffset(-this.offsetContentStartToFormatStart),
+            end: this.richTextBox.Document.ContentEnd,
+            color: this.currentlySelectedFormat.BackgroundBrush);
+    }
+
+    private static void RtbChangeTextBackground(RichTextBox rtb, TextPointer start, TextPointer end, Brush color)
+    {
+        // Get text selection
+        TextSelection textRange = rtb.Selection;
+        textRange.Select(start, end);
+
+        // Apply property to the selection:
+        textRange.ApplyPropertyValue(TextElement.BackgroundProperty, color);
+
+        // deselect
+        rtb.Selection.Select(rtb.Document.ContentEnd, rtb.Document.ContentEnd);
+    }
+
 }