WPF Textbox 自动判断范围实现颜色提示的功能

<TextBox HorizontalAlignment="Left" 
                             Height="23" Margin="20,192,0,0" 
                             TextWrapping="Wrap" 
                             Text="{Binding TestLiBin,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                             VerticalAlignment="Top" 
                             Width="65" 
                             RenderTransformOrigin="0.152,0.454"    
                             >
                        <TextBox.Style>
                            <Style TargetType="{x:Type TextBox}">
                                <Style.Triggers>

                                    <DataTrigger Binding="{Binding IsWarn,UpdateSourceTrigger=PropertyChanged}" Value="True">
                                        <Setter Property="Background" Value="Red"/>
                                    </DataTrigger>

                                    <DataTrigger Binding="{Binding IsWarn,UpdateSourceTrigger=PropertyChanged}" Value="False">
                                        <Setter Property="Background" Value="Green"/>
                                    </DataTrigger>

                                </Style.Triggers>
                            </Style>

                        </TextBox.Style>
                    </TextBox>

private int _Test=0;
        public int Test
        {
            get { return _Test; }
            set
            {
                _Test = value;
                if (_TestliBin > 100)
                {
                    IsWarn = true;
                }
                else
                {
                    IsWarn = false;
                }
                RaisePropertyChanged("Test");
            }
        }

        private bool _IsWarn = false;
        public bool IsWarn
        {
            get { return _IsWarn; }
            set
            {
                _IsWarn = value;
                RaisePropertyChanged("IsWarn");
            }
        }