¿Cómo se definen las restricciones de entrada de TextBox?

¿Cómo puedo restringir que TextBox acepte solamente letras mayúsculas, o por ejemplo dígitos, o prohíba poner cualquier carácter especial?

Seguro que es un pedazo de torta atrapar el evento TextInput y manejar el texto aquí, pero ¿es la manera correcta de hacer esto?

He mejorado la respuesta de Kent Boogaart al manejar las siguientes acciones que anteriormente podían causar la violación del patrón:

  • Retroceso
  • Seleccionar y arrastrar texto de una manera que puede violar el patrón
  • Cortar comando

Por ejemplo, la respuesta de Kent Boogaart permitió al usuario ingresar “ac” al primero ingresar “abc” y luego eliminar la “b” con el retroceso que viola la siguiente expresión regular

 ^(a|ab|abc)$ 

Uso (sin cambios):

Clase de máscara:

 public static class Masking { private static readonly DependencyPropertyKey _maskExpressionPropertyKey = DependencyProperty.RegisterAttachedReadOnly("MaskExpression", typeof(Regex), typeof(Masking), new FrameworkPropertyMetadata()); ///  /// Identifies the  dependency property. ///  public static readonly DependencyProperty MaskProperty = DependencyProperty.RegisterAttached("Mask", typeof(string), typeof(Masking), new FrameworkPropertyMetadata(OnMaskChanged)); ///  /// Identifies the  dependency property. ///  public static readonly DependencyProperty MaskExpressionProperty = _maskExpressionPropertyKey.DependencyProperty; ///  /// Gets the mask for a given . ///  ///  /// The  whose mask is to be retrieved. ///  ///  /// The mask, or  if no mask has been set. ///  public static string GetMask(TextBox textBox) { if (textBox == null) { throw new ArgumentNullException("textBox"); } return textBox.GetValue(MaskProperty) as string; } ///  /// Sets the mask for a given . ///  ///  /// The  whose mask is to be set. ///  ///  /// The mask to set, or  to remove any existing mask from . ///  public static void SetMask(TextBox textBox, string mask) { if (textBox == null) { throw new ArgumentNullException("textBox"); } textBox.SetValue(MaskProperty, mask); } ///  /// Gets the mask expression for the . ///  ///  /// This method can be used to retrieve the actual  instance created as a result of setting the mask on a . ///  ///  /// The  whose mask expression is to be retrieved. ///  ///  /// The mask expression as an instance of , or  if no mask has been applied to . ///  public static Regex GetMaskExpression(TextBox textBox) { if (textBox == null) { throw new ArgumentNullException("textBox"); } return textBox.GetValue(MaskExpressionProperty) as Regex; } private static void SetMaskExpression(TextBox textBox, Regex regex) { textBox.SetValue(_maskExpressionPropertyKey, regex); } private static void OnMaskChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) { var textBox = dependencyObject as TextBox; var mask = e.NewValue as string; textBox.PreviewTextInput -= textBox_PreviewTextInput; textBox.PreviewKeyDown -= textBox_PreviewKeyDown; DataObject.RemovePastingHandler(textBox, Pasting); DataObject.RemoveCopyingHandler(textBox, NoDragCopy); CommandManager.RemovePreviewExecutedHandler(textBox, NoCutting); if (mask == null) { textBox.ClearValue(MaskProperty); textBox.ClearValue(MaskExpressionProperty); } else { textBox.SetValue(MaskProperty, mask); SetMaskExpression(textBox, new Regex(mask, RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace)); textBox.PreviewTextInput += textBox_PreviewTextInput; textBox.PreviewKeyDown += textBox_PreviewKeyDown; DataObject.AddPastingHandler(textBox, Pasting); DataObject.AddCopyingHandler(textBox, NoDragCopy); CommandManager.AddPreviewExecutedHandler(textBox, NoCutting); } } private static void NoCutting(object sender, ExecutedRoutedEventArgs e) { if(e.Command == ApplicationCommands.Cut) { e.Handled = true; } } private static void NoDragCopy(object sender, DataObjectCopyingEventArgs e) { if (e.IsDragDrop) { e.CancelCommand(); } } private static void textBox_PreviewTextInput(object sender, TextCompositionEventArgs e) { var textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); if (maskExpression == null) { return; } var proposedText = GetProposedText(textBox, e.Text); if (!maskExpression.IsMatch(proposedText)) { e.Handled = true; } } private static void textBox_PreviewKeyDown(object sender, KeyEventArgs e) { var textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); if (maskExpression == null) { return; } string proposedText = null; //pressing space doesn't raise PreviewTextInput, reasons here http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/446ec083-04c8-43f2-89dc-1e2521a31f6b?prof=required if (e.Key == Key.Space) { proposedText = GetProposedText(textBox, " "); } // Same story with backspace else if(e.Key == Key.Back) { proposedText = GetProposedTextBackspace(textBox); } if (proposedText != null && proposedText != string.Empty && !maskExpression.IsMatch(proposedText)) { e.Handled = true; } } private static void Pasting(object sender, DataObjectPastingEventArgs e) { var textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); if (maskExpression == null) { return; } if (e.DataObject.GetDataPresent(typeof(string))) { var pastedText = e.DataObject.GetData(typeof(string)) as string; var proposedText = GetProposedText(textBox, pastedText); if (!maskExpression.IsMatch(proposedText)) { e.CancelCommand(); } } else { e.CancelCommand(); } } private static string GetProposedTextBackspace(TextBox textBox) { var text = GetTextWithSelectionRemoved(textBox); if (textBox.SelectionStart > 0 && textBox.SelectionLength == 0) { text = text.Remove(textBox.SelectionStart-1, 1); } return text; } private static string GetProposedText(TextBox textBox, string newText) { var text = GetTextWithSelectionRemoved(textBox); text = text.Insert(textBox.CaretIndex, newText); return text; } private static string GetTextWithSelectionRemoved(TextBox textBox) { var text = textBox.Text; if (textBox.SelectionStart != -1) { text = text.Remove(textBox.SelectionStart, textBox.SelectionLength); } return text; } } 

Cambié el código de VitalyB para admitir temas de color. En lugar de bloquear la entrada del usuario si no cumple con la secuencia de comandos RegEx, solo resalta el cuadro de texto. El cuadro de texto será el tema predeterminado sin interacción, y luego se cambiará a verde claro o rojo dependiendo del valor una vez que se establezca la entrada. También puede establecer el error y pasar los colores programáticamente con:

 b:ColorMasking.PassColor = "Hexadecimal Value" b:ColorMasking.FailColor = "Hexadecimal Value" 

La clase está abajo:

 public class ColorMasking : DependencyObject { private static readonly DependencyPropertyKey _maskExpressionPropertyKey = DependencyProperty.RegisterAttachedReadOnly("MaskExpression", typeof(Regex), typeof(ColorMasking), new FrameworkPropertyMetadata()); ///  /// Identifies the  dependency property. ///  /// public static readonly DependencyProperty PassColorProperty = DependencyProperty.RegisterAttached("PassColor", typeof(string), typeof(ColorMasking), new PropertyMetadata("#99FF99")); public static void SetPassColor(DependencyObject obj, string passColor) { obj.SetValue(PassColorProperty, passColor); } public static string GetPassColor(DependencyObject obj) { return (string)obj.GetValue(PassColorProperty); } public static readonly DependencyProperty FailColorProperty = DependencyProperty.RegisterAttached("FailColor", typeof(string), typeof(ColorMasking), new PropertyMetadata("#FFCCFF")); public static void SetFailColor(DependencyObject obj, string failColor) { obj.SetValue(FailColorProperty, failColor); } public static string GetFailColor(DependencyObject obj) { return (string)obj.GetValue(FailColorProperty); } public static readonly DependencyProperty MaskProperty = DependencyProperty.RegisterAttached("Mask", typeof(string), typeof(ColorMasking), new FrameworkPropertyMetadata(OnMaskChanged)); private static void OnPassColorChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) { var textBox = dependencyObject as TextBox; var color = e.NewValue as string; textBox.SetValue(PassColorProperty, color); } ///  /// Identifies the  dependency property. ///  public static readonly DependencyProperty MaskExpressionProperty = _maskExpressionPropertyKey.DependencyProperty; ///  /// Gets the mask for a given . ///  ///  /// The  whose mask is to be retrieved. ///  ///  /// The mask, or  if no mask has been set. ///  public static string GetMask(TextBox textBox) { if (textBox == null) { throw new ArgumentNullException("textBox"); } return textBox.GetValue(MaskProperty) as string; } ///  /// Sets the mask for a given . ///  ///  /// The  whose mask is to be set. ///  ///  /// The mask to set, or  to remove any existing mask from . ///  public static void SetMask(TextBox textBox, string mask) { if (textBox == null) { throw new ArgumentNullException("textBox"); } textBox.SetValue(MaskProperty, mask); } ///  /// Gets the mask expression for the . ///  ///  /// This method can be used to retrieve the actual  instance created as a result of setting the mask on a . ///  ///  /// The  whose mask expression is to be retrieved. ///  ///  /// The mask expression as an instance of , or  if no mask has been applied to . ///  public static Regex GetMaskExpression(TextBox textBox) { if (textBox == null) { throw new ArgumentNullException("textBox"); } return textBox.GetValue(MaskExpressionProperty) as Regex; } private static void SetMaskExpression(TextBox textBox, Regex regex) { textBox.SetValue(_maskExpressionPropertyKey, regex); } private static void OnMaskChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) { var textBox = dependencyObject as TextBox; var mask = e.NewValue as string; textBox.PreviewTextInput -= textBox_PreviewTextInput; textBox.PreviewKeyDown -= textBox_PreviewKeyDown; DataObject.RemovePastingHandler(textBox, Pasting); DataObject.RemoveCopyingHandler(textBox, NoDragCopy); CommandManager.RemovePreviewExecutedHandler(textBox, NoCutting); if (mask == null) { textBox.ClearValue(MaskProperty); textBox.ClearValue(MaskExpressionProperty); } else { textBox.SetValue(MaskProperty, mask); SetMaskExpression(textBox, new Regex(mask, RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace)); textBox.PreviewTextInput += textBox_PreviewTextInput; textBox.PreviewKeyDown += textBox_PreviewKeyDown; DataObject.AddPastingHandler(textBox, Pasting); DataObject.AddCopyingHandler(textBox, NoDragCopy); CommandManager.AddPreviewExecutedHandler(textBox, NoCutting); } } private static void NoCutting(object sender, ExecutedRoutedEventArgs e) { if (e.Command == ApplicationCommands.Cut) { e.Handled = true; } } private static void NoDragCopy(object sender, DataObjectCopyingEventArgs e) { if (e.IsDragDrop) { e.CancelCommand(); } } private static void textBox_PreviewTextInput(object sender, TextCompositionEventArgs e) { var textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); string passHex = (string)textBox.GetValue(PassColorProperty); string failHex = (string)textBox.GetValue(FailColorProperty); Color passColor = Extensions.ToColorFromHex(passHex); Color failColor = Extensions.ToColorFromHex(failHex); if (maskExpression == null) { return; } var proposedText = GetProposedText(textBox, e.Text); if (!maskExpression.IsMatch(proposedText)) { textBox.Background = new SolidColorBrush(failColor); } else { textBox.Background = new SolidColorBrush(passColor); } } private static void textBox_PreviewKeyDown(object sender, KeyEventArgs e) { var textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); string passHex = (string)textBox.GetValue(PassColorProperty); string failHex = (string)textBox.GetValue(FailColorProperty); Color passColor = Extensions.ToColorFromHex(passHex); Color failColor = Extensions.ToColorFromHex(failHex); if (maskExpression == null) { return; } string proposedText = null; //pressing space doesn't raise PreviewTextInput, reasons here http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/446ec083-04c8-43f2-89dc-1e2521a31f6b?prof=required if (e.Key == Key.Space) { proposedText = GetProposedText(textBox, " "); } // Same story with backspace else if (e.Key == Key.Back) { proposedText = GetProposedTextBackspace(textBox); } if (proposedText != null && !maskExpression.IsMatch(proposedText)) { textBox.Background = new SolidColorBrush(failColor); } else { textBox.Background = new SolidColorBrush(passColor); } } private static void Pasting(object sender, DataObjectPastingEventArgs e) { TextBox textBox = sender as TextBox; var maskExpression = GetMaskExpression(textBox); string passHex = (string)textBox.GetValue(PassColorProperty); string failHex = (string)textBox.GetValue(FailColorProperty); Color passColor = Extensions.ToColorFromHex(passHex); Color failColor = Extensions.ToColorFromHex(failHex); if (maskExpression == null) { return; } if (e.DataObject.GetDataPresent(typeof(string))) { var pastedText = e.DataObject.GetData(typeof(string)) as string; var proposedText = GetProposedText(textBox, pastedText); if (!maskExpression.IsMatch(proposedText)) { textBox.Background = new SolidColorBrush(failColor); } else { textBox.Background = new SolidColorBrush(passColor); } } else { textBox.Background = new SolidColorBrush(failColor); } } private static string GetProposedTextBackspace(TextBox textBox) { var text = GetTextWithSelectionRemoved(textBox); if (textBox.SelectionStart > 0) { text = text.Remove(textBox.SelectionStart - 1, 1); } return text; } private static string GetProposedText(TextBox textBox, string newText) { var text = GetTextWithSelectionRemoved(textBox); text = text.Insert(textBox.CaretIndex, newText); return text; } private static string GetTextWithSelectionRemoved(TextBox textBox) { var text = textBox.Text; if (textBox.SelectionStart != -1) { text = text.Remove(textBox.SelectionStart, textBox.SelectionLength); } return text; } } 

Para ejecutar, el script requiere una clase escrita por Aaron C, explicada aquí: Silverlight / WPF establece elipse con el color hexadecimal que se muestra aquí: http://www.wiredprairie.us/blog/index.php/archives/659

El código está debajo en caso de que el sitio se mueva alguna vez:

 public static class Extensions { public static void SetFromHex(this Color c, string hex) { Color c1 = ToColorFromHex(hex); cA = c1.A; cR = c1.R; cG = c1.G; cB = c1.B; } public static Color ToColorFromHex(string hex) { if (string.IsNullOrEmpty(hex)) { throw new ArgumentNullException("hex"); } // remove any "#" characters while (hex.StartsWith("#")) { hex = hex.Substring(1); } int num = 0; // get the number out of the string if (!Int32.TryParse(hex, System.Globalization.NumberStyles.HexNumber, null, out num)) { throw new ArgumentException("Color not in a recognized Hex format."); } int[] pieces = new int[4]; if (hex.Length > 7) { pieces[0] = ((num >> 24) & 0x000000ff); pieces[1] = ((num >> 16) & 0x000000ff); pieces[2] = ((num >> 8) & 0x000000ff); pieces[3] = (num & 0x000000ff); } else if (hex.Length > 5) { pieces[0] = 255; pieces[1] = ((num >> 16) & 0x000000ff); pieces[2] = ((num >> 8) & 0x000000ff); pieces[3] = (num & 0x000000ff); } else if (hex.Length == 3) { pieces[0] = 255; pieces[1] = ((num >> 8) & 0x0000000f); pieces[1] += pieces[1] * 16; pieces[2] = ((num >> 4) & 0x000000f); pieces[2] += pieces[2] * 16; pieces[3] = (num & 0x000000f); pieces[3] += pieces[3] * 16; } return Color.FromArgb((byte)pieces[0], (byte)pieces[1], (byte)pieces[2], (byte)pieces[3]); } } 
 private void TextBox1_SelectionChanged(object sender, RoutedEventArgs e) { string txt = TextBox1.Text; if (txt != "") { TextBox1.Text = Regex.Replace(TextBox1.Text, "[^0-9]", ""); if (txt != TextBox1.Text) { TextBox1.Select(TextBox1.Text.Length, 0); } } } 

Otra posible solución es utilizar una de las implementaciones wpf “Masked TextBox” utilizando la clase “MaskedTextProvider” que es utilizada por “MaskedTextBox” desde Winforms.

Aquí se encuentran dos posibles soluciones -> https://wpftoolkit.codeplex.com/wikipage?title=MaskedTextBox y aquí -> http://marlongrech.wordpress.com/2007/10/28/masked-textbox/

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