Create WPF TextBox that accepts only numbers [duplicate]

Question

I would like to create a TextBox that only accepts numeric values, in a specific range. What is the best way to implement such TextBox?

I thought about deriving TextBox and to override the validation and coercion of the TextProperty. However, I am not sure how to do this, and I understand that deriving WPF control is generally not recommended.

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Edit:
What I needed was a very basic textbox that filters out all key presses which are not digits. The easiest way to achieve it is to handle the TextBox.PreviewTextInput event:

private void textBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
    int result;
    if (!validateStringAsNumber(e.Text,out result,false))
    {
        e.Handled = true;
    }
}

(validateStringAsNumber is my function that primarily use Int.TryParse)

Some of the suggested solutions are probably better, but for the simple functionality I needed this solution is the easiest and quickest to implement while sufficient for my needs.

Answer 1

Most implementations I have seen so far are using the PreviewTextInput event to implement the correct mask behavior. This one inherits from TextBox and this one uses attached properties. Both use .Net's MaskedTextProvider to provide the correct mask behaviour, but if you just want a simple 'numbers only' textbox you don't need this class.

Answer 2

private void txt_TextChanged(object sender, TextChangedEventArgs e)
{
    TextBox textBox = sender as TextBox;
    int iValue = -1;

    if (Int32.TryParse(textBox.Text, out iValue) == false)
    {
         TextChange textChange = e.Changes.ElementAt<TextChange>(0);
         int iAddedLength = textChange.AddedLength;
         int iOffset = textChange.Offset;

         textBox.Text = textBox.Text.Remove(iOffset, iAddedLength);
    }
}