private static void HandleInputMaskDecimalKeyDown(Key key, TextBox textbox, string mask)
{
var startPosition = textbox.SelectionStart;
var isCurrency = mask == "$";
var isDecimal = mask == "%";
var numberFormat = CultureInfo.CurrentUICulture.NumberFormat;
var decimalSeparator = isCurrency ? numberFormat.CurrencyDecimalSeparator : numberFormat.NumberDecimalSeparator;
var lastInsertWasDecimalSeparator = false;
var valueIsNegative = false;
var valueWasNegativeOnEnter = false;
// Need to memorize how many digits there were to the left before this keystroke
var allChars = textbox.Text.ToCharArray().ToList();
var numberOfDigitsToTheLeft = 0;
for (var charCounter = 0; charCounter < startPosition; charCounter++)
{
if (char.IsDigit(allChars[charCounter]) || allChars[charCounter] == '-')
{
numberOfDigitsToTheLeft++;
}
}
// We check if the value is negative
if (allChars.Count > 0 && allChars[0] == '-')
{
valueIsNegative = true;
valueWasNegativeOnEnter = true;
}
// Special custom decimal handling
var currencySymbol = GetInputMaskCurrencySymbol(textbox);
if (string.IsNullOrEmpty(currencySymbol))
{
currencySymbol = numberFormat.CurrencySymbol;
SetInputMaskCurrencySymbol(textbox, currencySymbol); // So we have it for later
}
var newChar = KeyboardHelper.GetCharFromKey(key);
var sb = new StringBuilder(textbox.Text);
if (key == Key.Delete)
{
if (textbox.SelectionLength > 0)
{
sb.Remove(startPosition, textbox.SelectionLength);
for (var counter = 0; counter < textbox.SelectionLength; counter++)
{
allChars.RemoveAt(startPosition);
}
}
else
{
if (startPosition < sb.Length)
{
sb.Remove(startPosition, 1);
allChars.RemoveAt(startPosition);
}
}
if (allChars.Count == 0)
{
sb.Append("0");
}
}
else if (key == Key.Back)
{
if (textbox.SelectionLength > 0)
{
sb.Remove(startPosition, textbox.SelectionLength);
for (var counter = 0; counter < textbox.SelectionLength; counter++)
{
allChars.RemoveAt(startPosition);
}
}
else if (startPosition > 0)
{
if (startPosition - 1 < sb.Length)
{
sb.Remove(startPosition - 1, 1);
allChars.RemoveAt(startPosition - 1);
numberOfDigitsToTheLeft--;
}
}
if (allChars.Count == 0)
{
sb.Append("0");
}
}
else
{
// Need to handle selected text properly by replacing it with the new input
if (textbox.SelectionLength > 0 && !(newChar == '-' || newChar == '+'))
{
sb.Remove(startPosition, textbox.SelectionLength);
for (var counter = 0; counter < textbox.SelectionLength; counter++)
{
allChars.RemoveAt(startPosition);
}
if (allChars.Count == 0 && valueWasNegativeOnEnter)
{
valueWasNegativeOnEnter = false;
valueIsNegative = false;
}
}
if (char.IsDigit(newChar))
{
sb.Insert(startPosition, newChar);
numberOfDigitsToTheLeft++;
}
else if (GetInputMaskSupportsNegative(textbox) && newChar == '-')
{
// We need to make sure that the value is negative
valueIsNegative = true;
if (!valueWasNegativeOnEnter)
{
numberOfDigitsToTheLeft++;
}
}
else if (GetInputMaskSupportsNegative(textbox) && newChar == '+')
{
// We need to make sure that the value is positive
valueIsNegative = false;
if (valueWasNegativeOnEnter)
{
numberOfDigitsToTheLeft--;
if (numberOfDigitsToTheLeft < 0)
{
numberOfDigitsToTheLeft = 0;
}
}
}
else if (newChar.ToString() == decimalSeparator)
{
// If there is a decimal indicator to the left, we ignore the input
for (var counter = 0; counter < startPosition; counter++)
{
if (allChars[counter].ToString() == decimalSeparator)
{
SystemSounds.Beep.Play();
return;
}
}
// If there already is another decimal in the string (to the right), we need to get rid of it
var existingDecimalPosition = -1;
for (var counter = startPosition; counter < allChars.Count; counter++)
{
if (allChars[counter].ToString() == decimalSeparator)
{
existingDecimalPosition = counter;
}
}
if (existingDecimalPosition > -1)
{
sb.Remove(startPosition, existingDecimalPosition - startPosition + 1);
}
sb.Insert(startPosition, newChar);
lastInsertWasDecimalSeparator = true;
}
else
{
SystemSounds.Beep.Play();
}
}
var newText = sb.ToString();
if (isCurrency && newText.StartsWith(currencySymbol))
{
newText = newText.Substring(currencySymbol.Length).Trim();
}
if (valueIsNegative && !newText.StartsWith("-"))
{
newText = "-" + newText;
}
else if (!valueIsNegative && newText.StartsWith("-"))
{
newText = newText.Substring(1);
}
if (isDecimal && newText.EndsWith("%"))
{
newText = newText.Substring(0, newText.Length - 1);
}
decimal parsedValue;
if (decimal.TryParse(newText, out parsedValue))
{
var rightFormat = isCurrency ? StringHelper.Replicate("0", numberFormat.CurrencyDecimalDigits) : GetInputMaskDecimalFractionalMask(textbox);
newText = parsedValue.ToString(GetInputMaskDecimalCharacteristicMask(textbox) + "." + rightFormat);
if (isCurrency)
{
newText = currencySymbol + " " + newText;
}
if (isDecimal)
{
newText += "%";
}
textbox.SetValue(InputMaskIsValidatingProperty, true);
textbox.Text = newText;
SetTextUnmasked(textbox, parsedValue.ToString("###########0." + rightFormat));
textbox.SetValue(InputMaskIsValidatingProperty, false);
var newCaretIndex = 0;
var digitsFound = 0;
var newAllChars = newText.ToCharArray();
foreach (var newAllChar in newAllChars)
{
if (digitsFound >= numberOfDigitsToTheLeft)
{
break;
}
if (isCurrency)
{
if (newCaretIndex > currencySymbol.Length && char.IsDigit(newAllChar))
{
digitsFound++;
}
}
else if (char.IsDigit(newAllChar) || newAllChar == '-')
{
digitsFound++;
}
newCaretIndex++;
}
if (lastInsertWasDecimalSeparator)
{
newCaretIndex++;
}
textbox.CaretIndex = newCaretIndex;
}
else
{
SystemSounds.Beep.Play();
}
}
private static void HandleInputMaskKeyDown(object sender, KeyEventArgs e)
{
var textbox = sender as TextBox;
if (textbox == null)
{
return;
}
var mask = GetInputMask(textbox);
var provider = GetMaskedTextProvider(textbox, mask);
var startPosition = textbox.SelectionStart;
var startSelectionLength = textbox.SelectionLength;
var ignoreKeys = new List <Key> {
Key.LeftShift, Key.RightShift, Key.Tab, Key.Capital, Key.CapsLock, Key.Left, Key.Right, Key.Home, Key.End
};
if (ignoreKeys.Contains(e.Key))
{
return;
}
if (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl))
{
return;
}
if (e.Key == Key.Delete)
{
if (startSelectionLength > 0)
{
provider.RemoveAt(startPosition, startPosition + startSelectionLength);
}
else
{
provider.RemoveAt(startPosition);
}
}
else if (e.Key == Key.Back)
{
if (startPosition > 0)
{
if (startSelectionLength > 0)
{
provider.RemoveAt(startPosition, startPosition + startSelectionLength);
}
else
{
provider.RemoveAt(startPosition - 1);
}
}
}
else
{
var newChar = KeyboardHelper.GetCharFromKey(e.Key);
// TOOO: Want to handle special scenarios when the user hits .,/ or something similar, and those are indeed in the input mask. This will make it easier to enter numeric values and dates in natural fashion.
var specialChars = new List <char> {
'.', ',', '-', '/', '\\', '(', ')'
};
if (specialChars.Contains(newChar) && textbox.CaretIndex < mask.Length)
{
// We found a special character that may require special handling.
var remainingMask = mask.Substring(textbox.CaretIndex);
var shiftDistance = remainingMask.IndexOf(newChar);
if (shiftDistance > -1)
{
// We have discovered a keystroke with a special meaning, so we simply move the cursor to that position and carry on
if (newChar == '.' || newChar == ',')
{
// We handle this as a numeric entry, which means we have to clear out all the characters between the current location and the special char
provider.RemoveAt(startPosition, startPosition + shiftDistance);
provider.InsertAt(" ".Replicate(shiftDistance), 0);
textbox.SetValue(InputMaskIsValidatingProperty, true);
textbox.Text = provider.ToDisplayString();
textbox.SetValue(InputMaskIsValidatingProperty, false);
}
textbox.CaretIndex += shiftDistance + 1;
e.Handled = true;
return;
}
}
if (startSelectionLength > 0) // Looks like we are in replace mode
{
provider.RemoveAt(startPosition, startPosition + startSelectionLength);
}
provider.InsertAt(newChar, startPosition);
textbox.SetValue(InputMaskIsValidatingProperty, true);
textbox.Text = provider.ToDisplayString();
textbox.SetValue(InputMaskIsValidatingProperty, false);
var newCaretPosition = provider.FindAssignedEditPositionFrom(startPosition, true);
newCaretPosition++;
if (newCaretPosition > textbox.Text.Length - 1)
{
newCaretPosition = textbox.Text.Length - 1;
}
if (newCaretPosition < 0)
{
newCaretPosition = textbox.CaretIndex > 0 ? textbox.Text.Length : 0;
}
textbox.CaretIndex = newCaretPosition;
e.Handled = true;
}
}
private static void HandleInputMaskKeyDown(object sender, KeyEventArgs e)
{
if (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl))
{
return;
}
if (Keyboard.IsKeyDown(Key.LeftAlt) || Keyboard.IsKeyDown(Key.RightAlt))
{
return;
}
var ignoreKeys = new List <Key> {
Key.LeftShift, Key.RightShift, Key.Tab, Key.Capital, Key.CapsLock, Key.Left, Key.Right, Key.Home, Key.End, Key.LeftAlt, Key.RightAlt, Key.LeftCtrl, Key.RightCtrl
};
if (ignoreKeys.Contains(e.Key))
{
return;
}
var textbox = sender as TextBox;
if (textbox == null)
{
return;
}
var mask = GetInputMask(textbox);
if (mask == "d" || mask == "$" || mask == "%")
{
HandleInputMaskDecimalKeyDown(e.Key, textbox, mask);
e.Handled = true;
}
else
{
var startPosition = textbox.SelectionStart;
// We are using the default .NET MaskedTextProvider to provide this functionality
var provider = GetMaskedTextProvider(textbox, mask);
// Need to handle selected text properly by replacing it with the new input
if (e.Key == Key.Delete)
{
if (textbox.SelectionLength > 0)
{
provider.RemoveAt(startPosition, startPosition + textbox.SelectionLength - 1);
}
else
{
provider.RemoveAt(startPosition);
}
}
else if (e.Key == Key.Back)
{
if (startPosition > 0 || textbox.SelectionLength > 0)
{
if (textbox.SelectionLength > 0)
{
provider.RemoveAt(startPosition, startPosition + textbox.SelectionLength - 1);
}
else
{
provider.RemoveAt(startPosition - 1);
}
}
}
else
{
if (textbox.SelectionLength > 0)
{
provider.RemoveAt(startPosition, startPosition + textbox.SelectionLength - 1);
}
var newChar = KeyboardHelper.GetCharFromKey(e.Key);
if (provider.MaskFull)
{
provider.RemoveAt(provider.Length - 1);
}
provider.InsertAt(newChar, startPosition);
textbox.SetValue(InputMaskIsValidatingProperty, true);
textbox.Text = provider.ToDisplayString();
textbox.SetValue(InputMaskIsValidatingProperty, false);
var newCarotPosition = provider.FindAssignedEditPositionFrom(startPosition, true);
newCarotPosition++;
if (newCarotPosition > textbox.Text.Length - 1)
{
newCarotPosition = textbox.Text.Length - 1;
}
if (newCarotPosition < 0)
{
newCarotPosition = textbox.CaretIndex > 0 ? textbox.Text.Length : 0;
}
textbox.CaretIndex = newCarotPosition;
e.Handled = true;
}
textbox.SetValue(InputMaskIsValidatingProperty, true);
SetTextUnmasked(textbox, provider.ToString(false, false));
textbox.SetValue(InputMaskIsValidatingProperty, false);
}
}