Come definire restrizioni di ingresso TextBox?

Question

Come posso limitare TextBox per accettare solo lettere maiuscole, o per esempio le cifre, o non voglia mettere qualsiasi carattere speciale?

Certo, è un pezzo di torta per la cattura di evento TextInput e gestire il testo qui, ma è il modo corretto di fare questo?

Answer 1

L'ho fatto in passato con un comportamento annesso, che può essere utilizzato in questo modo:

<TextBox b:Masking.Mask="^\p{Lu}*$"/>

Il codice di comportamento in allegato è simile al seguente:

/// <summary>
/// Provides masking behavior for any <see cref="TextBox"/>.
/// </summary>
public static class Masking
{
    private static readonly DependencyPropertyKey _maskExpressionPropertyKey = DependencyProperty.RegisterAttachedReadOnly("MaskExpression",
        typeof(Regex),
        typeof(Masking),
        new FrameworkPropertyMetadata());

    /// <summary>
    /// Identifies the <see cref="Mask"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MaskProperty = DependencyProperty.RegisterAttached("Mask",
        typeof(string),
        typeof(Masking),
        new FrameworkPropertyMetadata(OnMaskChanged));

    /// <summary>
    /// Identifies the <see cref="MaskExpression"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MaskExpressionProperty = _maskExpressionPropertyKey.DependencyProperty;

    /// <summary>
    /// Gets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask, or <see langword="null"/> if no mask has been set.
    /// </returns>
    public static string GetMask(TextBox textBox)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        return textBox.GetValue(MaskProperty) as string;
    }

    /// <summary>
    /// Sets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be set.
    /// </param>
    /// <param name="mask">
    /// The mask to set, or <see langword="null"/> to remove any existing mask from <paramref name="textBox"/>.
    /// </param>
    public static void SetMask(TextBox textBox, string mask)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        textBox.SetValue(MaskProperty, mask);
    }

    /// <summary>
    /// Gets the mask expression for the <see cref="TextBox"/>.
    /// </summary>
    /// <remarks>
    /// This method can be used to retrieve the actual <see cref="Regex"/> instance created as a result of setting the mask on a <see cref="TextBox"/>.
    /// </remarks>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask expression is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask expression as an instance of <see cref="Regex"/>, or <see langword="null"/> if no mask has been applied to <paramref name="textBox"/>.
    /// </returns>
    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);

        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);
        }
    }

    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;
        }

        //pressing space doesn't raise PreviewTextInput - no idea why, but we need to handle
        //explicitly here
        if (e.Key == Key.Space)
        {
            var proposedText = GetProposedText(textBox, " ");

            if (!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 GetProposedText(TextBox textBox, string newText)
    {
        var text = textBox.Text;

        if (textBox.SelectionStart != -1)
        {
            text = text.Remove(textBox.SelectionStart, textBox.SelectionLength);
        }

        text = text.Insert(textBox.CaretIndex, newText);

        return text;
    }
}

Answer 2

Ho migliorato la risposta di Kent Boogaart gestendo anche le seguenti azioni che in precedenza potrebbero causare il modello da violata:

• Backspace
• Selezione e il testo trascinando in un modo che può violare il modello
• comando Taglia

Per esempio, la risposta di Kent Boogaart permesso all'utente di inserire "ac" immettendo prima "abc" e poi cancellare la "b" con il backspace che viola la seguente espressione regolare

^(a|ab|abc)$

Utilizzo (invariato):

<TextBox b:Masking.Mask="^\p{Lu}*$"/>

class Mask:

public static class Masking
{
    private static readonly DependencyPropertyKey _maskExpressionPropertyKey = DependencyProperty.RegisterAttachedReadOnly("MaskExpression",
            typeof(Regex),
            typeof(Masking),
            new FrameworkPropertyMetadata());

    /// <summary>
    /// Identifies the <see cref="Mask"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MaskProperty = DependencyProperty.RegisterAttached("Mask",
            typeof(string),
            typeof(Masking),
            new FrameworkPropertyMetadata(OnMaskChanged));

    /// <summary>
    /// Identifies the <see cref="MaskExpression"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MaskExpressionProperty = _maskExpressionPropertyKey.DependencyProperty;

    /// <summary>
    /// Gets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask, or <see langword="null"/> if no mask has been set.
    /// </returns>
    public static string GetMask(TextBox textBox)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        return textBox.GetValue(MaskProperty) as string;
    }

    /// <summary>
    /// Sets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be set.
    /// </param>
    /// <param name="mask">
    /// The mask to set, or <see langword="null"/> to remove any existing mask from <paramref name="textBox"/>.
    /// </param>
    public static void SetMask(TextBox textBox, string mask)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        textBox.SetValue(MaskProperty, mask);
    }

    /// <summary>
    /// Gets the mask expression for the <see cref="TextBox"/>.
    /// </summary>
    /// <remarks>
    /// This method can be used to retrieve the actual <see cref="Regex"/> instance created as a result of setting the mask on a <see cref="TextBox"/>.
    /// </remarks>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask expression is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask expression as an instance of <see cref="Regex"/>, or <see langword="null"/> if no mask has been applied to <paramref name="textBox"/>.
    /// </returns>
    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;
    }
}

Answer 3

Ho cambiato il codice di VitalyB per sostenere Temi colore. Invece di bloccare l'input dell'utente, se non soddisfa lo script RegEx, solo evidenzia la casella di testo. La casella di testo sarà il valore predefinito tema senza interazione, e quindi il default è una luce verde o rossa a seconda del valore dopo l'ingresso è impostato. È anche possibile impostare il fallire e passare colori programatically con:

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

La classe è qui sotto:

public class ColorMasking : DependencyObject
{
    private static readonly DependencyPropertyKey _maskExpressionPropertyKey = DependencyProperty.RegisterAttachedReadOnly("MaskExpression",
            typeof(Regex),
            typeof(ColorMasking),
            new FrameworkPropertyMetadata());

    /// <summary>
    /// Identifies the <see cref="Mask"/> dependency property.
    /// </summary>
    /// 
    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);
    }

    /// <summary>
    /// Identifies the <see cref="MaskExpression"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MaskExpressionProperty = _maskExpressionPropertyKey.DependencyProperty;

    /// <summary>
    /// Gets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask, or <see langword="null"/> if no mask has been set.
    /// </returns>
    public static string GetMask(TextBox textBox)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        return textBox.GetValue(MaskProperty) as string;
    }

    /// <summary>
    /// Sets the mask for a given <see cref="TextBox"/>.
    /// </summary>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask is to be set.
    /// </param>
    /// <param name="mask">
    /// The mask to set, or <see langword="null"/> to remove any existing mask from <paramref name="textBox"/>.
    /// </param>
    public static void SetMask(TextBox textBox, string mask)
    {
        if (textBox == null)
        {
            throw new ArgumentNullException("textBox");
        }

        textBox.SetValue(MaskProperty, mask);
    }

    /// <summary>
    /// Gets the mask expression for the <see cref="TextBox"/>.
    /// </summary>
    /// <remarks>
    /// This method can be used to retrieve the actual <see cref="Regex"/> instance created as a result of setting the mask on a <see cref="TextBox"/>.
    /// </remarks>
    /// <param name="textBox">
    /// The <see cref="TextBox"/> whose mask expression is to be retrieved.
    /// </param>
    /// <returns>
    /// The mask expression as an instance of <see cref="Regex"/>, or <see langword="null"/> if no mask has been applied to <paramref name="textBox"/>.
    /// </returns>
    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;
    }
}

Per eseguire, lo script richiede una classe scritta da Aaron C, spiegato qui: Silverlight / WPF imposta ellisse con colore esadecimale mostrato qui: http: //www.wiredprairie.us/blog/index.php/archives/659

Il codice è seguito nel caso in cui il sito è mai mosso:

public static class Extensions
{
    public static void SetFromHex(this Color c, string hex)
    {
        Color c1 = ToColorFromHex(hex);

        c.A = c1.A;
        c.R = c1.R;
        c.G = c1.G;
        c.B = 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]);
    }

}

Answer 4

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);
        }
    }
}

Answer 5

Ecco l'ennesima versione delle soluzioni esistenti qui. E 'un comportamento che simula un evento "TextChanging" che fornisce il vecchio testo, il nuovo testo e una bandiera per annullare la modifica. In questo modo siamo in grado di implementare qualsiasi filtro che vogliamo.

mi sono liberato del gestore "PreviewKeyDown" utilizzato solo per il carattere spazio. TextBox sembra gestire tutto con i comandi di instradamento e "Spazio" ha un suo commmand, anche se non è pubblico. Ho anche aggiunto il supporto per le scorciatoie da tastiera supplementi come "Ctrl + Backspace" (Cancella la parola precedente).

public class TextChangingBehavior : Behavior<TextBox>
{
    public event EventHandler<TextChangingEventArgs> TextChanging;

    protected override void OnAttached()
    {
        base.OnAttached();

        AssociatedObject.PreviewTextInput += OnPreviewTextInput;
        CommandManager.AddPreviewExecutedHandler(AssociatedObject, OnPreviewExecutedHandler);
        DataObject.AddCopyingHandler(AssociatedObject, OnCopying);
        DataObject.AddPastingHandler(AssociatedObject, OnPasting);
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();

        AssociatedObject.PreviewTextInput -= OnPreviewTextInput;
        CommandManager.RemovePreviewExecutedHandler(AssociatedObject, OnPreviewExecutedHandler);
        DataObject.RemoveCopyingHandler(AssociatedObject, OnCopying);
        DataObject.RemovePastingHandler(AssociatedObject, OnPasting);
    }

    #region Text

    private enum CharCategory
    {
        LetterOrDigit,
        Whitespace,
        Other
    }

    private CharCategory GetCharCategory(char c)
    {
        if (char.IsLetterOrDigit(c))
            return CharCategory.LetterOrDigit;
        else if (char.IsWhiteSpace(c))
            return CharCategory.Whitespace;
        else
            return CharCategory.Other;
    }

    private string GetText(string input = null)
    {
        var box = AssociatedObject;
        var text = box.Text ?? string.Empty;
        if (input != null)
        {
            // Delete selection
            var deleteCount = box.SelectionLength;
            if (deleteCount > 0)
                text = text.Remove(box.SelectionStart, deleteCount);
            // Insert input
            if (input.Length > 0)
                text = text.Insert(box.CaretIndex, input);
        }
        return text;
    }

    #endregion

    private void OnPreviewExecutedHandler(object sender, ExecutedRoutedEventArgs e)
    {
        var box = AssociatedObject;
        var selectionExists = box.SelectionLength > 0;
        var caretIndex = box.CaretIndex;
        string newText = null;

        if (e.Command == ApplicationCommands.Cut)
        {
            if (selectionExists)
                newText = GetText(string.Empty);
        }
        else if (e.Command == EditingCommands.Backspace)
        {
            if (selectionExists)
                newText = GetText(string.Empty);
            else if (caretIndex > 0)
                newText = GetText().Remove(caretIndex - 1, 1);
        }
        else if (e.Command == EditingCommands.Delete)
        {
            if (selectionExists)
                newText = GetText(string.Empty);
            else
            {
                newText = GetText();
                if (caretIndex >= newText.Length)
                    newText = null;
                else
                    newText = newText.Remove(caretIndex, 1);
            }
        }
        else if (e.Command == EditingCommands.DeletePreviousWord)
        {
            if (selectionExists)
                newText = GetText(string.Empty);
            else if (caretIndex > 0)
            {
                newText = GetText();
                var startIndex = caretIndex;
                // Include whitespaces
                do
                    startIndex--;
                while (startIndex > 0 && char.IsWhiteSpace(newText[startIndex]));
                // Include the next block
                var currentCategory = GetCharCategory(newText[startIndex]);
                while (startIndex > 0 && GetCharCategory(newText[startIndex - 1]) == currentCategory)
                    startIndex--;

                newText = newText.Remove(startIndex, caretIndex - startIndex);
            }
        }
        else if (e.Command == EditingCommands.DeleteNextWord)
        {
            if (selectionExists)
                newText = GetText(string.Empty);
            else
            {
                newText = GetText();
                if (caretIndex >= newText.Length)
                    newText = null;
                else
                {
                    var endIndex = caretIndex + 1;
                    // Include the current block
                    var currentCategory = GetCharCategory(newText[caretIndex]);
                    while (endIndex < newText.Length && GetCharCategory(newText[endIndex]) == currentCategory)
                        endIndex++;
                    // Include whitespaces
                    while (endIndex < newText.Length && char.IsWhiteSpace(newText[endIndex]))
                        endIndex++;

                    newText = newText.Remove(caretIndex, endIndex - caretIndex);
                }
            }
        }
        else if (e.Command is RoutedUICommand cmd && new[] { "Space", "ShiftSpace" }.Contains(cmd.Name))
        {
            newText = GetText(" ");
        }

        if (newText != null && OnProcessChange(newText))
            e.Handled = true;
    }

    private void OnCopying(object sender, DataObjectCopyingEventArgs e)
    {
        if (e.IsDragDrop)
        {
            if (OnProcessChange(GetText(string.Empty)))
                e.CancelCommand();
        }
    }

    private void OnPasting(object sender, DataObjectPastingEventArgs e)
    {
        if (e.DataObject.GetDataPresent(typeof(string)))
        {
            if (OnProcessChange(GetText((string)e.DataObject.GetData(typeof(string)))))
                e.CancelCommand();
        }
    }

    private void OnPreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        if (!string.IsNullOrEmpty(e.Text))
        {
            if (OnProcessChange(GetText(e.Text)))
                e.Handled = true;
        }
    }

    private bool OnProcessChange(string newValue)
    {
        var oldValue = GetText();

        if (string.Equals(oldValue, newValue, StringComparison.Ordinal))
            return false;
        else
        {
            var args = new TextChangingEventArgs(oldValue, newValue);
            OnTextChanging(args);
            return args.Cancel;
        }
    }

    protected virtual void OnTextChanging(TextChangingEventArgs e)
    {
        TextChanging?.Invoke(this, e);
    }
}

public class TextChangingEventArgs : EventArgs
{
    public string OldValue { get; }

    public string NewValue { get; }

    public bool Cancel { get; set; }

    public TextChangingEventArgs(string oldValue, string newValue)
    {
        OldValue = oldValue;
        NewValue = newValue;
    }
}

Answer 6

Un'altra possibile soluzione è quella di utilizzare uno dei "mascherato TextBox" wpf attuazione utilizzando la classe "MaskedTextProvider" utilizzato dal "MaskedTextBox" da Winforms.

Due possibili soluzioni si trovano qui -> https://wpftoolkit.codeplex.com/wikipage? title = MaskedTextBox e qui -> http: //marlongrech.wordpress .com / 2007/10/28 / mascherati-testo /