TextBox, WPF

With TextBoxes, we present a user-editable box for input. And in some cases, a TextBox is an effective way to display program output.

It is easy to add a TextBox to a WPF program—please create a C# WPF project. From the Toolbox panel, drag a TextBox control to the designer window.

Attribute example

Now, in the XAML markup, changed the Text attribute to be an empty string. The Text property indicates the string displayed into the TextBox.

<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBox HorizontalAlignment="Left"
                 Height="23"
                 Margin="10,10,0,0"
                 TextWrapping="Wrap"
                 Text=""
                 VerticalAlignment="Top"
                 Width="120"
                 TextChanged="TextBox_TextChanged"/>

    </Grid>
</Window>
using System.Windows;
using System.Windows.Controls;

namespace WpfApplication2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            // ... Get control that raised this event.
            var textBox = sender as TextBox;
            // ... Change Window Title.
            this.Title = textBox.Text + "[Length = " + textBox.Text.Length.ToString() + "]";
        }
    }
}

Text

When accessed, the Text property always returns a string that indicates the characters currently inside the TextBox. It can also be assigned—this changes the current contents.

TextChanged

This event handler is triggered whenever the Text property of the TextBox changes. It is triggered at startup if a default Text attribute is set.

We discovered how to capture user input into this TextBox (with TextChanged). We finally read the Text property, and assigned the Window Title.