我建议您在下面的示例代码中添加另一个Dependency属性，我将其命名为Value还可以用逗号或NumberFormatInfo.CurrentInfo.NumberDecimalSeparator格式化您的电话号码并通过两个属性SelectionLength和SelectionStart控制插入符的位置更改.最后，有关更多详细信息和完整代码，请参见 WPF可屏蔽数字输入文本框

地区价值属性

 公共静态只读DependencyProperty ValueProperty =DependencyProperty.Register("Value"，typeof(double)，typeof(NumericTextBox)，new PropertyMetadata(new Double()，OnValueChanged));私有静态无效OnValueChanged(DependencyObject sender，DependencyPropertyChangedEventArgs args){//var numericBoxControl =(NumericTextBox)sender;}公共双重价值{get {return(double)GetValue(ValueProperty);}设置{SetValue(ValueProperty，value);文字= value.ToString("###，###，###");}} 

endregion

 受保护的重写void OnPreviewTextInput(TextCompositionEventArgs e){base.OnPreviewTextInput(e);var txt = e.Text.Replace(，"，");e.Handled =！IsTextAllowed(txt);如果(IsTextAllowed(txt)){如果(Text.Length == 3){文字= Text.Insert(1，，");SelectionLength = 1;SelectionStart + = Text.Length;}}}受保护的重写void OnPreviewKeyDown(KeyEventArgs e){base.OnPreviewKeyDown(e);如果(e.Key == Key.Back){如果(Text.Length == 5){文字= Text.Replace(，"，");SelectionLength = 1;SelectionStart + = Text.Length;}}}受保护的重写void OnTextChanged(TextChangedEventArgs e){var txt = Text.Replace(，"，");SetValue(ValueProperty，txt.Length == 0?0:double.Parse(txt));base.OnTextChanged(e);}私人静态布尔IsTextAllowed(字符串文本){尝试{double.Parse(text);返回true；}捕获(FormatException){返回false；}} 

I want create a custom control for Numeric Text box with dependency property in WPF , in my solution , I add one WPF application and custom control (WPF) ,then in public class , I create dependency property ....

Now I don't know how can i write my rule for text box and which event is true?

Another question : What is my rule for numeric text box , that this text box must be give number and . and Separating .this custom Text box is for accounting system.

public static readonly DependencyProperty NumberTextbox; 
static Numeric()
{
    DefaultStyleKeyProperty.OverrideMetadata(typeof(Numeric), new FrameworkPropertyMetadata(typeof(Numeric)));
    FrameworkPropertyMetadata metadata = new FrameworkPropertyMetadata("Enter Your Text", OnKeyDown);
    NumberTextbox =DependencyProperty.Register("Text", typeof(TextBox), typeof(FrameworkElement), metadata);
}


public string NumberTXT
{
    get { return (string)GetValue(NumberTextbox); }
    set { SetValue(NumberTextbox, value); }
} 

I recommend to you add another Dependency Property in example code below I named it Value Also format your number by comma or NumberFormatInfo.CurrentInfo.NumberDecimalSeparator and control caret location changes by two property SelectionLength and SelectionStart. Finally for more detail and complete code WPF Maskable Number Entry TextBox

region Value property

    public static readonly DependencyProperty ValueProperty =
        DependencyProperty.Register("Value", typeof(double), typeof(NumericTextBox), new PropertyMetadata(new Double(), OnValueChanged));

    private static void OnValueChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
    {
        //var numericBoxControl = (NumericTextBox)sender;
    }
    public double Value
    {
        get { return (double)GetValue(ValueProperty); }
        set { SetValue(ValueProperty, value); Text = value.ToString("###,###,###"); }
    }

endregion

    protected override void OnPreviewTextInput(TextCompositionEventArgs e)
    {
        base.OnPreviewTextInput(e);
        var txt = e.Text.Replace(",", "");
        e.Handled = !IsTextAllowed(txt);
        if (IsTextAllowed(txt))
        {
            if (Text.Length == 3)
            {
                Text = Text.Insert(1,",");
                SelectionLength = 1;
                SelectionStart += Text.Length;
            }
        }
    }

    protected override void OnPreviewKeyDown(KeyEventArgs e)
    {
        base.OnPreviewKeyDown(e);
        if (e.Key == Key.Back)
        {
            if (Text.Length == 5)
            {
                Text = Text.Replace(",", "");
                SelectionLength = 1;
                SelectionStart += Text.Length;
            }
        }
    }



    protected override void OnTextChanged(TextChangedEventArgs e)
    {            
        var txt = Text.Replace(",", "");
        SetValue(ValueProperty, txt.Length==0?0:double.Parse(txt));
        base.OnTextChanged(e);
    }

    private static bool IsTextAllowed(string text)
    {
        try
        {
            double.Parse(text);
            return true;
        }
        catch (FormatException)
        {
            return false;
        }
    }