WPF > Windows > DependencyProperty
DependencyProperty is a property that can be set through methods such as, styling, data binding, animation, and inheritance.
Example: Create a numeric TextBox with DependencyProperty
Create new WPF User Control Library
NumericTextBox.xaml
<TextBox x:Class="NumericTextBox.NumericTextBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
>
</TextBox>
NumericTextBox.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace NumericTextBox
{
/// <summary>
/// Interaction logic for NumericTextBox.xaml
/// </summary>
public partial class NumericTextBox : TextBox
{
public NumericTextBox()
{
InitializeComponent();
this.PreviewTextInput += OnPreviewTextInput;
}
/// <summary>
/// The max value property
/// </summary>
public static readonly DependencyProperty MaxValueProperty =
DependencyProperty.Register("MaxValue", typeof(double?),
typeof(NumericTextBox), new UIPropertyMetadata(null));
public double? MaxValue
{
get { return (double?)GetValue(MaxValueProperty); }
set { SetValue(MaxValueProperty, value); }
}
/// <summary>
/// The min value property
/// </summary>
public static readonly DependencyProperty MinValueProperty =
DependencyProperty.Register("MinValue", typeof(double?),
typeof(NumericTextBox), new UIPropertyMetadata(null));
public double? MinValue
{
get { return (double?)GetValue(MinValueProperty); }
set { SetValue(MinValueProperty, value); }
}
private bool CheckNumeric(string text)
{
var regex = new Regex("[^0-9.]+");
return !regex.IsMatch(text);
}
private void OnPreviewTextInput(object sender, TextCompositionEventArgs e)
{
if (this.CheckNumeric(e.Text))
{
if (e.Text == "." && this.Text.Contains("."))
e.Handled = true;
else
{
// Check
min value
if (MinValue != null && Convert.ToDouble(this.Text + e.Text) <
MinValue)
{
this.Text = MinValue.ToString();
this.SelectionStart = this.Text.Length;
e.Handled = true;
}
// Check max value
if (MaxValue != null && Convert.ToDouble(this.Text + e.Text) >
MaxValue)
{
this.Text = MaxValue.ToString();
this.SelectionStart = this.Text.Length;
e.Handled = true;
}
}
}
else
e.Handled = true;
}
}
}
MainWindow.xaml
You can set MinValue and MaxValue properties
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:NumericTextBox="clr-namespace:NumericTextBox;assembly=NumericTextBox" x:Class="WpfApplication3.MainWindow"
Title="MainWindow" Height="350" Width="525">
<Grid>
<NumericTextBox:NumericTextBox
HorizontalAlignment="Left" Margin="98,89,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top"
Width="201" MinValue="1" MaxValue="100000"/>
</Grid>
</Window>
