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<h1>Descend</h1>
<p>ExtObjectContainer#descend method allows you to navigate from a persistent object to it's members without activating or instantiating intermediate objects.</p>
<p MadCap:conditions="Global.Primary:java" />
<p MadCap:conditions="Primary..NET,Primary.c#,Primary.All languages">
<pre class="prettyprint" xml:space="preserve">UtilityExample.cs: TestDescend
public static void TestDescend()
{
StoreSensorPanel();
IConfiguration configuration = Db4oFactory.NewConfiguration();
configuration.ActivationDepth(1);
IObjectContainer db = Db4oFactory.OpenFile(
configuration, Db4oFileName);
try
{
System.Console.WriteLine("Object container activation depth = 1");
IObjectSet result = db.QueryByExample(new SensorPanel(1));
SensorPanel spParent = (SensorPanel)result[0];
SensorPanel spDescend = (SensorPanel)db.Ext().
Descend((Object)spParent, new String[] {"_next","_next",
"_next","_next","_next"});
db.Ext().Activate(spDescend, 5);
System.Console.WriteLine(spDescend);
}
finally
{
db.Close();
}
}</pre>
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<p MadCap:conditions="Global.Primary:cs" />
<p MadCap:conditions="Primary..NET,Primary.VB.NET,Primary.All languages">
<pre class="prettyprint lang-vb" xml:space="preserve">UtilityExample.vb: TestDescend
Public Shared Sub TestDescend()
StoreSensorPanel()
Dim configuration As IConfiguration = Db4oFactory.NewConfiguration()
configuration.ActivationDepth(1)
Dim db As IObjectContainer = Db4oFactory.OpenFile(configuration, _
Db4oFileName)
Try
System.Console.WriteLine("Object container activation depth = 1")
Dim result As IObjectSet = db.QueryByExample(New SensorPanel(1))
Dim spParent As SensorPanel = CType(result(0), SensorPanel)
Dim fields() As String = {"_next", "_next", "_next", "_next", "_next"}
Dim spDescend As SensorPanel = CType(db.Ext().Descend( _
CType(spParent, Object), fields), Object)
db.Ext().Activate(spDescend, 5)
System.Console.WriteLine(spDescend)
Finally
db.Close()
End Try
End Sub</pre>
</p>
<p MadCap:conditions="Global.Primary:vb" />
<p>Navigating in this way can save you resources on activating only the objects you really need.</p>
<p MadCap:conditions="Primary.Online">Download example code:</p>
<p MadCap:conditions="Primary.Online">
<MadCap:conditionalText MadCap:conditions="Primary..NET,Primary.VB.NET,Primary.All languages"><a href="utilityvb.zip">VB.NET </a>
</MadCap:conditionalText>
<MadCap:conditionalText MadCap:conditions="Primary..NET,Primary.c#,Primary.All languages"><a href="utilitycs.zip">c# </a>
</MadCap:conditionalText>
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