WPF完成加载动画

 <Controls:MetroWindow x:Class="MyControlLibrarys.LoadDialog"

    
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    
     xmlns:local="clr-namespace:MyControlLibrarys"      
    
     Title="正在加载" WindowStyle="None" Height="180" Width="430" ShowMaxRestoreButton="False" ShowMinButton="False" ShowCloseButton="False"
    
     WindowSt