Wpf Decimals Styling - wpf

Question

I want to Style a TextBox with decimal places like this:
How can I do that ?

Answer 1

You can extend the TextBox like this.
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
public class DecimalTextBox : TextBox
{
public static readonly DependencyProperty FloatColorProperty = DependencyProperty.Register("FloatColor", typeof(Color), typeof(DecimalTextBox), new FrameworkPropertyMetadata(Colors.Red));
public Color FloatColor
{
get { return (Color)GetValue(FloatColorProperty); }
set { SetValue(FloatColorProperty, value); }
}
protected TextBlock _textBlock;
protected FrameworkElement _textBoxView;
public DecimalTextBox()
{
_textBlock = new TextBlock() { Margin = new Thickness(1, 0, 0, 0) };
Loaded += ExTextBox_Loaded;
}
private void ExTextBox_Loaded(object sender, RoutedEventArgs e)
{
Loaded -= ExTextBox_Loaded;
// hide the original drawing visuals, by setting opacity on their parent
var visual = this.GetChildOfType<DrawingVisual>();
_textBoxView = (FrameworkElement)visual.Parent;
_textBoxView.Opacity = 0;
// add textblock to do the text drawing for us
var grid = this.GetChildOfType<Grid>();
if (grid.Children.Count >= 2)
grid.Children.Insert(1, _textBlock);
else
grid.Children.Add(_textBlock);
}
protected override void OnLostKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnLostKeyboardFocus(e);
_textBoxView.Opacity = 0;
_textBlock.Visibility = Visibility.Visible;
}
protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnGotKeyboardFocus(e);
_textBoxView.Opacity = 1;
_textBlock.Visibility = Visibility.Collapsed;
}
protected override void OnTextChanged(TextChangedEventArgs e)
{
base.OnTextChanged(e);
// making sure text on TextBlock is updated as per TextBox
var dotPos = Text.IndexOf('.');
var textPart1 = dotPos == -1 ? Text : Text.Substring(0, dotPos + 1);
var textPart2 = (dotPos == -1 || dotPos >= (Text.Length-1)) ? null : Text.Substring(dotPos + 1);
_textBlock.Inlines.Clear();
_textBlock.Inlines.Add(new Run {
Text = textPart1,
FontFamily = FontFamily,
FontSize = FontSize,
Foreground = Foreground });
if (textPart2 != null)
_textBlock.Inlines.Add(new Run {
Text = textPart2,
FontFamily = FontFamily,
TextDecorations = System.Windows.TextDecorations.Underline,
BaselineAlignment = BaselineAlignment.TextTop,
FontSize = FontSize * 5/6,
Foreground = new SolidColorBrush(FloatColor) });
}
}
public static class HelperExtensions
{
public static T GetChildOfType<T>(this DependencyObject depObj) where T : DependencyObject
{
if (depObj == null) return null;
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
var child = VisualTreeHelper.GetChild(depObj, i);
var result = (child as T) ?? GetChildOfType<T>(child);
if (result != null) return result;
}
return null;
}
}
XAML code usage
<local:DecimalTextBox FloatColor="Maroon" />
And your output should look like this:
Update 05/17
Explanation: As you can see from the image, the DecimalTextBox displays the text in formatted mode only when its not focused.
I had initially developed the control to support formatting during edit (which can still be done by commenting the methods OnLostKeyboardFocus, and OnGotKeyboardFocus) - but because of the font-size difference the cursor positioning was getting slightly skewed, which in turn would translate to bad user experience.
Therefore, implemented the swap logic during GotFocus and LostFocus to fix that.

Answer 2

You can't do that with a TextBox, because TextBox only accepts color changes to the entire text. You should try with RichTextBox, that allows loop throug TextRange's. Look at this sample of syntax highlighting with a RichTextBox.
I actually understood how it works and made it:
private void richTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
richTextBox.TextChanged -= this.richTextBox_TextChanged;
if (richTextBox.Document == null)
return;
TextRange documentRange = new TextRange(richTextBox.Document.ContentStart, richTextBox.Document.ContentEnd);
documentRange.ClearAllProperties();
int dotIndex = documentRange.Text.IndexOf(".");
if(dotIndex == -1)
{
richTextBox.TextChanged += this.richTextBox_TextChanged;
return;
}
TextPointer dotStart = GetPoint(richTextBox.Document.ContentStart, dotIndex);
TextPointer dotEnd = dotStart.GetPositionAtOffset(1, LogicalDirection.Forward);
TextRange initRange = new TextRange(richTextBox.Document.ContentStart, dotStart);
TextRange endRange = new TextRange(dotEnd, richTextBox.Document.ContentEnd);
endRange.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.Red));
richTextBox.TextChanged += this.richTextBox_TextChanged;
}
Suscribe the textbox TextChanged event to this method. You can now set the styles you want to every part of the text like this:
To change the last part (after the dot char) endRange.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.Red));
To change the first part (before the dot char) is the same but for the initRange variable. If you want to change the 'dot' style, then create a new TextRange with dotStart and dotEnd TextPointers and apply styles to it. You can do other things like change font style, size, etc.
This code result looks like this:
All this is just for style. For checking that is a number is up to you.

Answer 3

I would define a custom control with this main properties:
FloatNumber: the original number, that should be a DependencyProperty to be Bind from the control.
NumberOfDecimalDigits: a number to choose how many decimal digits to represent, that should be a DependencyProperty to be Bind from the control.
FirstPart: a string that will contain the first part of the decimal number
Decimals: a string that will contain the decimal digits of FloatNumber
Of course this is just a scratch, those properties could be implemented better to extract FloatNumber parts.
public partial class DecimalDisplayControl : UserControl, INotifyPropertyChanged
{
public DecimalDisplayControl()
{
InitializeComponent();
(Content as FrameworkElement).DataContext = this;
}
public static readonly DependencyProperty NumberOfDecimalDigitsProperty =
DependencyProperty.Register(
"NumberOfDecimalDigits", typeof(string),
typeof(DecimalDisplayControl), new PropertyMetadata(default(string), OnFloatNumberChanged));
public static readonly DependencyProperty FloatNumberProperty =
DependencyProperty.Register(
"FloatNumber", typeof(string),
typeof(DecimalDisplayControl), new PropertyMetadata(default(string), OnFloatNumberChanged));
private static void OnFloatNumberChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
(d as DecimalDisplayControl).OnFloatNumberChanged();
}
protected void OnFloatNumberChanged()
{
int numberOfDecimalDigits = Convert.ToInt32(NumberOfDecimalDigits);
float fullNumber = Convert.ToSingle(FloatNumber);
float firstPart = (float)Math.Truncate(fullNumber);
float fullDecimalPart = fullNumber - firstPart;
int desideredDecimalPart = (int)(fullDecimalPart * Math.Pow(10, numberOfDecimalDigits));
FirstPart = $"{firstPart}.";
Decimals = desideredDecimalPart.ToString();
}
public string FloatNumber
{
get => (string)GetValue(FloatNumberProperty);
set { SetValue(FloatNumberProperty, value); }
}
public string NumberOfDecimalDigits
{
get => (string)GetValue(NumberOfDecimalDigitsProperty);
set { SetValue(NumberOfDecimalDigitsProperty, value); }
}
private string _firstPart;
public string FirstPart
{
get => _firstPart;
set
{
if (_firstPart == value)
return;
_firstPart = value;
OnPropertyChanged();
}
}
private string _decimals;
public string Decimals
{
get => _decimals;
set
{
if (_decimals == value)
return;
_decimals = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Its XAML:
<UserControl
x:Class="WpfApp1.CustomControls.DecimalDisplayControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<StackPanel
HorizontalAlignment="Center"
VerticalAlignment="Center"
Orientation="Horizontal">
<TextBlock
FontSize="20"
Foreground="Black"
Text="{Binding FirstPart}" />
<TextBlock
FontSize="10"
Foreground="Red"
Text="{Binding Decimals}"
TextDecorations="Underline" />
</StackPanel>
</UserControl>
Then you can use it in your page and bind a property to make it change dynamically:
<Grid>
<StackPanel VerticalAlignment="Center" Orientation="Vertical">
<customControls:DecimalDisplayControl
HorizontalAlignment="Center"
VerticalAlignment="Center"
NumberOfDecimalDigits="2"
FloatNumber="{Binding MyNumber}" />
<TextBox
Width="200"
VerticalAlignment="Center"
Text="{Binding MyNumber, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel>
</Grid>
The final result: