Silverlight中以客户端加载另一项目客户端（先登录后加载的一般实现）

近几日，本人在对一个老的Silverlight的GIS项目进行维护，发现该项目的实现是先把所有的资源加载至客户端，其中包括登录部分和业务实现部分，我就在想可不可以把登录部分和业务实现部分开来。如果用户输入的账号密码正确才开始加载业务实现方面的资源（1.由于Silverlight的运行资源的加载是一次性的。2.现在主流的实现都是如此）

如下是我在代码中的实现

private const string odll = "SilverlightApplication2.dll";
private const string LoaderPageName = "SilverlightApplication2.MainPage";

private void button1_Click(object sender, RoutedEventArgs e)
{
const string name = "SilverlightApplication2.xap";
var uri = new Uri(name, UriKind.Relative);
WebClient webClient=new WebClient();
if (webClient.IsBusy)
{
webClient.CancelAsync();
}
webClient.OpenReadCompleted -= new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.DownloadProgressChanged -= new DownloadProgressChangedEventHandler(webClient_DownloadProgressChanged);
webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(webClient_DownloadProgressChanged);
webClient.OpenReadAsync(uri);
}

void webClient_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
//throw new NotImplementedException();
this.textBlock1.Text = "已经加载 " + e.ProgressPercentage;
if (e.ProgressPercentage == 100)
{
return;
}
}

void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
//throw new NotImplementedException();
try
{
Stream streamLoadXap = e.Result;

if (streamLoadXap != null)
{
Assembly assemblyDll = LoadAssemblyFromXap(streamLoadXap, odll);

if (assemblyDll != null)
{
UIElement elementXapMain = assemblyDll.CreateInstance(LoaderPageName) as UIElement;

if (elementXapMain != null)
{
this.Content = elementXapMain;
}
else
{
MessageBox.Show("惨了，程序加载失败了！！！");
}
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

/// <summary>
/// 从程序中获取程序集
/// </summary>
/// <param name="streamLoadXap"></param>
/// <param name="strAssemblyName"></param>
/// <returns></returns>
public Assembly LoadAssemblyFromXap(Stream streamLoadXap, string strAssemblyName)
{
try
{
Stream streamXml = Application.GetResourceStream(new StreamResourceInfo(streamLoadXap, null), new Uri("AppManifest.xaml", UriKind.Relative)).Stream;
String appManifestString = new StreamReader(streamXml).ReadToEnd();

XElement deploymentRoot = XDocument.Parse(appManifestString).Root;  //创建XML文件，并增加加载的程序集内容新内容
if (deploymentRoot != null)
{
List<XElement> deploymentParts = (from assemblyParts in deploymentRoot.Elements().Elements() select assemblyParts).ToList();
Assembly asm = null;

foreach (var xElement in deploymentParts)
{
XAttribute xAttribute = xElement.Attribute("Source");
if (xAttribute != null)
{
string source = xAttribute.Value;
AssemblyPart assemblyPart = new AssemblyPart {Source = source};

StreamResourceInfo sri = Application.GetResourceStream(new StreamResourceInfo(streamLoadXap, "application/binary"), new Uri(source, UriKind.Relative));

if (source.Equals(odll))
{
asm = assemblyPart.Load(sri.Stream);
}
else
{
assemblyPart.Load(sri.Stream);
}
}
}

return asm;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return null;
}
return null;
}

当然还有其他功能可以实现，比如地址的跳转等。