WPF

<ResourceDictionary>
    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="/Assembly;component/NewSkin.xaml" />
    </ResourceDictionary.MergedDictionaries>
</ResourceDictionary>

<!--Global View Model Locator-->
<vm:ViewModelLocator x:Key="Locator"
                     d:IsDataSource="True" />

class FrameworkElement : UIElement
    {
        public static readonly DependencyProperty NumberProperty;

        public FrameworkElement() { }

        static FrameworkElement()
        {
            FrameworkPropertyMetadata metadata =
                new FrameworkPropertyMetadata(Double.NaN,
                                              FrameworkPropertyMetadataOptions.AffectsMeasure);

            NumberProperty = DependencyProperty.Register("Number",//Propertie name
                                                          typeof(Double),//Data used by the prpertie
                                                          typeof(FrameworkElement),//The type that owns the propertie
                                                          metadata,//Meta data object
                                                          new ValidateValueCallback(FrameworkElement.IsNumberValid));//Validation callback

        }

        public Double Number
        {
            set { SetValue(NumberProperty, value); }
            get { return (Double)GetValue(NumberProperty); }
        }


        private static Boolean IsNumberValid(object value)
        {
            Double number = (Double)value;

            if ((number < 0) || (number > 100))
                return false;
            return true;
        }
    }

When we copy the content of multiple cells (Rows X Columns) with border (Outer Border / All borders) from excel sheet and paste the copied content in to System.Windows.Controls.RichTextBox in the WPF window the content are pasted inside the text box with some of the borders are not present in the pasted content.  We have also tried approach like converting the Clipboard text to XAML / HTML but no luck