void Control_EditingChanged(object sender, EventArgs e)
{
var element = ((FormattedNumberEntry)Element);
// Oh boy, thank you internet: http://stackoverflow.com/a/34922332
// 1. Stop listening for changes on our control Text property
if (!element.ShouldReactToTextChanges)
{
return;
}
element.ShouldReactToTextChanges = false;
// 2. Get the current cursor position
var selectedRange = Control.SelectedTextRange;
// 3. Take the control’s text, lets name it oldText
var oldText = Control.Text;
// 4. Parse oldText into a number, lets name it number
var number = FormattedNumberEntry.DumbParse(oldText);
element.Value = number;
// 5. Format number, and place the formatted text in newText
var newText = $"{number:#,##0}";
// 6. Set the Text property of our control to newText
Control.Text = newText;
// 7. Calculate the new cursor position
var change = -1 * (oldText.Length - newText.Length);
var newPosition = Control.GetPosition(selectedRange.Start, (nint)change);
// 8. Set the new cursor position
if (newPosition != null) // before we fail miserably
{
Control.SelectedTextRange = Control.GetTextRange(newPosition, newPosition);
}
// 9. Start listening for changes on our control’s Text property
element.ShouldReactToTextChanges = true;
}
private void Control_TextChanged(object sender, Windows.UI.Xaml.Controls.TextChangedEventArgs e)
{
var element = ((FormattedNumberEntry)Element);
// 1. Stop listening for changes on our control Text property
if (!element.ShouldReactToTextChanges)
{
return;
}
element.ShouldReactToTextChanges = false;
// 2. Get the current cursor position
var cursorPosition = Control.SelectionStart;
// 3. Take the control’s text, lets name it oldText
var oldText = Control.Text;
// 4. Parse oldText into a number, lets name it number
var number = FormattedNumberEntry.DumbParse(oldText);
element.Value = number;
// 5. Format number, and place the formatted text in newText
var newText = $"{number:#,##0}";
// 6. Set the Text property of our control to newText
Control.Text = newText;
// 7. Calculate the new cursor position
var change = -1 * (oldText.Length - newText.Length);
if (cursorPosition + change < 0)
{
change = 0;
}
// 8. Set the new cursor position
Control.SelectionStart = cursorPosition + change;
// 9. Start listening for changes on our control’s Text property
element.ShouldReactToTextChanges = true;
}