如何删除文本框中键入的最后一个字符

Question

I want to remove the last character someone types in a textbox. For example if someone types in an empty textbox "abcd", i want to remove the letter "d", or if in a textbox containing "abcd", the user types a 1 like in here: "ab1cd", i want to remove that 1

Answer 1

Listen to the TextChanged event of the textbox, and save the change that happened:

public partial class MainWindow : Window
{
    private ICollection<TextChange> _latestChange = null;

    public MainWindow()
    {
        InitializeComponent();

        myTextBox.TextChanged += (o, a) =>
        {
            _latestChange = a.Changes;
        };
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        if (_latestChange != null)
        {
            var change = _latestChange.FirstOrDefault(); // Just take first change
            if (change.AddedLength > 0) // If text was removed, ignore
            {
                myTextBox.Text = myTextBox.Text.Remove(change.Offset, change.AddedLength);
            }
        }
    }
}

Answer 2

private void button1_Click(object sender, EventArgs e)
{
    string newstring = textBox1.Text;
    for(int i = 0; i<=9; i++)
    {
        if(newstring.Contains(i.ToString()))
        {
            int start = newstring.IndexOf(i.ToString());
            newstring = newstring.Remove(start, 1);
        }
    }
    textBox1.Text = newstring.Remove(newstring.Length - 1);
}

This will remove the last letter and any kind of number in the string. Hope it helps.