Quick Silverlight Tip: Initialization Parameters
The scenario: you developing Silverlight application, and you need to pass some parameter inside - for example to define which page will be shown, or to pass user credentials, after he already logged-in in previous non-Silverlight part of application.
So, ho you could do it? The answer is pretty simple - "initParams" in Silverlight object construction.
The parameters could be named, and not named.
Named parameters example:
<object data="data:application/x-silverlight," type="application/x-silverlight-2-b2" width="100%" height="100%">
<param name="source" value="ClientBin/InitParams.xap"/>
<param name="onerror" value="onSilverlightError" />
<param name="background" value="white" />
<param name="initParams" value="UserName=Alex, AuthID=123, eMail=alexg@sela.co.il" />Non-Name parameters example:
<object data="data:application/x-silverlight," type="application/x-silverlight-2-b2" width="100%" height="100%">
<param name="source" value="ClientBin/InitParams.xap"/>
<param name="onerror" value="onSilverlightError" />
<param name="background" value="white" />
<param name="initParams" value="Alex,123,alexg@sela.co.il" />Once those parameters being passed to application it could be used in code-behind. There is two ways to get those parameters: as a part of StartupEventArgs (in Application_Startup event) or get them directly from Silverlight plug-in.
Here is first way to do it:
//In App.Xaml.cs
private void Application_Startup(object sender, StartupEventArgs e)
{
//In my example, if there is InitParams specified call an overloaded constructor
if (e.InitParams.Count > 0)
this.RootVisual = new Page(e.InitParams);
else
this.RootVisual = new Page();
}
//In Page.Xaml.cs - somewhere in class:
IDictionary<string, string> initParams;
public Page(IDictionary<string, string> parameters)
{
//do whatever need to be done - for example...
initParams = parameters;
}
This approach is good when we use named parameters, because unnamed parameters will return InitParams.Count = 0.
To deal with unnamed parameters, we could get them from plugin properties:
public Page()
{
InitializeComponent();
string sParameters = System.Windows.Browser.HtmlPage.Plugin.GetProperty("initParams").ToString();
//If parameters return
if (sParameters.Length > 0)
{
//Process them....
string[] parameters = sParameters.Split(new char[] { ',' });
if (null != parameters)
{
//In my case I'm making unnamed parameters behave closely to named parameters
initParams = new Dictionary<string, string>();
int counter = 0;
//I'm adding every value with some genrated key to dictionary collection,
//which will enable me to use them exactly like named.
foreach (var item in parameters)
{
string key = "KEY_" + counter;
string val = item;
initParams.Add(key, val);
counter++;
}
}
}We done... Now we can accept parameters and use it.
Enjoy,
Alex