How Do I Make a textbox Class Which Only Takes Numeric Data in WPF Application

• Download source code - 61.1 KB

Introduction

Firstly, we try to create new WPF application. And add a new class. In my example class, the name is Class1.

Background

textBox.PreviewTextInput += 
new System.Windows.Input.TextCompositionEventHandler(Class1.PreviewTextInput);

Each textBox using Class1, it will have numerical property.

Using the Code

In MainWindow (WPF page), I added my code in constructor. But you can add where you need this.

WPF Page

public MainWindow()
        {
            InitializeComponent();
            textBox.Text = "";
            textBox.PreviewTextInput += 
            new System.Windows.Input.TextCompositionEventHandler(Class1.PreviewTextInput);
        }

Class

public static void PreviewTextInput(object sender, TextCompositionEventArgs e)
       {
           bool approvedDecimalPoint = false;

           if (e.Text == ".")
           {
               if (!((TextBox)sender).Text.Contains("."))
                   approvedDecimalPoint = true;
           }

           if (!(char.IsDigit(e.Text, e.Text.Length - 1) || approvedDecimalPoint))
               e.Handled = true;
       }

Points of Interest

Add libraries.

using System.Windows.Controls;
using System.Windows.Input;

History

• 3^rd August, 2016: Initial version