默认初始屏幕体验
在托管 API 下为 Silverlight 定义的默认体验是：超出某一时间阈值（约为 0.5 秒）的任何加载都将在内容区域中显示基于 XAML 的动画。显示该默认动画和初始化序列的 XAML 被硬编码到 Silverlight 插件中。
为了替换默认初始屏幕，您为在 HTML 中定义 object 元素的 Silverlight 插件的 splashScreenSource 参数提供一个值。或者，用于 Silverlight 的 ASP.NET 控件将定义一些 API，这些 API 将所需的初始屏幕相关参数设置到其在 HTML 中的输出 object 元素中。
以上是其的官方解释，简单的说呢就是可以 利用初始屏幕来制作自定义的loading效果。
官方的中文文档写的相当详细了，这里我就不在做重复的熬述。
http://msdn.microsoft.com/zh-cn/library/cc838130%28VS.95%29.aspx
做法
1.先自己做一个想要的初始屏幕的xaml（在blend中创建一个silverlight 1的项目，用blend画一个loading界面）
<
Canvas
xmlns ="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x ="http://schemas.microsoft.com/winfx/2006/xaml"
x:Name ="parentCanvas"
xmlns:d ="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc ="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable ="d" >
< Grid x:Name ="LayoutRoot" >
< Grid HorizontalAlignment ="Center" VerticalAlignment ="Center" Width ="280" Height ="37.807" >
< Canvas Width ="280" Height ="37.807" >
< TextBlock FontSize ="22" Foreground ="#FF949494" TextWrapping ="Wrap" >
< Run Text ="SilverAlbum" />
</ TextBlock >
< TextBlock x:Name ="StatusText"
FontSize ="10"
Foreground ="#FF949494"
TextWrapping ="Wrap"
Canvas.Left ="150" Text =""
Canvas.Top ="13.16" />
< Canvas Canvas.Top ="25.807" Width ="280" Height ="12" >
< Rectangle Stroke ="#FF949494" StrokeThickness ="2" Width ="280" Height ="12" />
< Rectangle x:Name ="ProgressBar"
Width ="272"
Height ="4"
Fill ="#FF949494" Canvas.Left ="4.26" Canvas.Top ="4" >
< Rectangle.RenderTransform >
< TransformGroup >
< ScaleTransform x:Name ="ProgressBarTransform" ScaleY ="1" ScaleX ="0" />
< SkewTransform />
< RotateTransform />
< TranslateTransform Y ="0" X ="0" />
</ TransformGroup >
</ Rectangle.RenderTransform >
</ Rectangle >
</ Canvas >
</ Canvas >
</ Grid >
</ Grid >
</ Canvas >
xmlns ="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x ="http://schemas.microsoft.com/winfx/2006/xaml"
x:Name ="parentCanvas"
xmlns:d ="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc ="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable ="d" >
< Grid x:Name ="LayoutRoot" >
< Grid HorizontalAlignment ="Center" VerticalAlignment ="Center" Width ="280" Height ="37.807" >
< Canvas Width ="280" Height ="37.807" >
< TextBlock FontSize ="22" Foreground ="#FF949494" TextWrapping ="Wrap" >
< Run Text ="SilverAlbum" />
</ TextBlock >
< TextBlock x:Name ="StatusText"
FontSize ="10"
Foreground ="#FF949494"
TextWrapping ="Wrap"
Canvas.Left ="150" Text =""
Canvas.Top ="13.16" />
< Canvas Canvas.Top ="25.807" Width ="280" Height ="12" >
< Rectangle Stroke ="#FF949494" StrokeThickness ="2" Width ="280" Height ="12" />
< Rectangle x:Name ="ProgressBar"
Width ="272"
Height ="4"
Fill ="#FF949494" Canvas.Left ="4.26" Canvas.Top ="4" >
< Rectangle.RenderTransform >
< TransformGroup >
< ScaleTransform x:Name ="ProgressBarTransform" ScaleY ="1" ScaleX ="0" />
< SkewTransform />
< RotateTransform />
< TranslateTransform Y ="0" X ="0" />
</ TransformGroup >
</ Rectangle.RenderTransform >
</ Rectangle >
</ Canvas >
</ Canvas >
</ Grid >
</ Grid >
</ Canvas >
2.在html页面中silverlightHost的地方修改以下代码
3.编写js文件（做过silverlight1.0开发的朋友应该不会陌生，就是通过js来控制silverlight中的元素）
function
onSourceDownloadProgressChanged(sender, eventArgs) {
sender.findName( " LayoutRoot " ).Width = document.body.clientWidth;
sender.findName( " LayoutRoot " ).Height = document.body.clientHeight;
sender.findName( " StatusText " ).Text = Math.round((eventArgs.progress * 1000 )) / 10 + " percent loaded " ;
sender.findName( " ProgressBarTransform " ).ScaleX = eventArgs.progress;
}
sender.findName( " LayoutRoot " ).Width = document.body.clientWidth;
sender.findName( " LayoutRoot " ).Height = document.body.clientHeight;
sender.findName( " StatusText " ).Text = Math.round((eventArgs.progress * 1000 )) / 10 + " percent loaded " ;
sender.findName( " ProgressBarTransform " ).ScaleX = eventArgs.progress;
}
这样就完成了一个自定义的loading效果。 ：） 很简单吧
看到这里再请看看不用SplashScreenSource的做法
