WPF，TextBlock ，ToolTip 显示

<TextBlock Text="{Binding OutPointString}" Width="80" TextTrimming="CharacterEllipsis" TextAlignment="Left" VerticalAlignment="Center">
                                    <ToolTipService.ToolTip>
                                        <ToolTip Style="{DynamicResource NormalToolTip}">
                                            <TextBlock Text="{Binding OutPointString}" MaxWidth="300" TextWrapping="Wrap"/>
                                        </ToolTip>
                                    </ToolTipService.ToolTip>   
                                </TextBlock>