What is --- End of inner exception stack trace ---

Why is my Stack trace split into 2 half's, delimited by “End of inner exception stack trace “??

Example StackTrace from one of my older applications, that manages GPS points

Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionHandlingException: The type 'Old.Base.DataAccess.ExceptionHandler.OracleExceptionHandler, Old.DataAccess, Version=2.0.0.11969, Culture=neutral, PublicKeyToken=null' cannot be resolved. Please verify the spelling is correct or that the full type name is provided. ---> System.ArgumentException: The type 'Old.Base.DataAccess.ExceptionHandler.OracleExceptionHandler, Old.DataAccess, Version=2.0.0.11969, Culture=neutral, PublicKeyToken=null' cannot be resolved. Please verify the spelling is correct or that the full type name is provided.
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.AssemblyQualifiedTypeNameConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   at System.ComponentModel.TypeConverter.ConvertFrom(Object value)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.NameTypeConfigurationElement.get_Type()
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.CustomProviderAssembler`3.Assemble(IBuilderContext context, TConfiguration objectConfiguration, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.AssemblerBasedObjectFactory`2.Create(IBuilderContext context, TConfiguration objectConfiguration, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntryCustomFactory.Create(IBuilderContext context, ExceptionTypeData objectConfiguration, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyCustomFactory.CreateObject(IBuilderContext context, String name, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.ConfiguredObjectStrategy.BuildUp(IBuilderContext context, Type t, Object existing, String id)
   at Microsoft.Practices.ObjectBuilder.SingletonStrategy.BuildUp(IBuilderContext context, Type typeToBuild, Object existing, String idToBuild)
   at Microsoft.Practices.ObjectBuilder.BuilderStrategy.BuildUp(IBuilderContext context, Type typeToBuild, Object existing, String idToBuild)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.ConfigurationNameMappingStrategy.BuildUp(IBuilderContext context, Type t, Object existing, String id)
   at Microsoft.Practices.ObjectBuilder.BuilderBase`1.DoBuildUp(IReadWriteLocator locator, Type typeToBuild, String idToBuild, Object existing, PolicyList[] transientPolicies)
   at Microsoft.Practices.ObjectBuilder.BuilderBase`1.BuildUp(IReadWriteLocator locator, Type typeToBuild, String idToBuild, Object existing, PolicyList[] transientPolicies)
   at Microsoft.Practices.ObjectBuilder.BuilderBase`1.BuildUp[TTypeToBuild](IReadWriteLocator locator, String idToBuild, Object existing, PolicyList[] transientPolicies)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.EnterpriseLibraryFactory.BuildUp[T](IReadWriteLocator locator, String id, IConfigurationSource configurationSource)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.LocatorNameTypeFactoryBase`1.Create(String name)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName, ExceptionPolicyFactory factory)
   --- End of inner exception stack trace ---
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName, ExceptionPolicyFactory factory)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException(Exception exceptionToHandle, String policyName)
   at Old.SLFD.PlanManager.DataAccess.OracleODP.ImageSaverDAO.InsertImage(InsertImageParameter imageParam)
   at Old.SLFD.PlanManager.BusinessLogic.ImageManipulationBL.ImportImages(String elencoPtFilename, String imagefolder)
   at Old.SLFD.PlanManager.WinForms.Controls.CreationAndImportImages.StartImport()
   at Old.SLFD.PlanManager.WinForms.Controls.CreationAndImportImages.toolbarsManager_ToolClick_1(Object sender, ToolClickEventArgs e)
   at Infragistics.Win.UltraWinToolbars.ToolClickEventHandler.Invoke(Object sender, ToolClickEventArgs e)
   at Infragistics.Win.UltraWinToolbars.UltraToolbarsManager.OnToolClick(ToolClickEventArgs e)
   at Infragistics.Win.UltraWinToolbars.UltraToolbarsManager.FireEvent(ToolbarEventIds id, EventArgs e)
   at Infragistics.Win.UltraWinToolbars.ToolBase.OnToolClick()
   at Infragistics.Win.UltraWinToolbars.ButtonToolUIElement.DoClickProcessing(MouseEventArgs e)
   at Infragistics.Win.UltraWinToolbars.ButtonToolUIElement.OnMouseUp(MouseEventArgs e)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseUpHelper(Object sender, MouseEventArgs e)
   at Infragistics.Win.ControlUIElementBase.ProcessMouseUp(Object sender, MouseEventArgs e)
   at Infragistics.Win.Utilities.ProcessEvent(Control control, ProcessEvent eventToProcess, EventArgs e)
   at Infragistics.Win.UltraControlBase.OnMouseUp(MouseEventArgs e)
   at Infragistics.Win.UltraWinToolbars.UltraToolbarsDockArea.OnMouseUp(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Figure: ArgumentException in my code.

Long time ago, I was wondering why?

The obvious reason for this, is that an Exception can hold an InnerException (see property in screenshot).

Figure: Reflector showing type: Exception

This happens if the exception is caught by some other code in the middle (e.g. Business layer; see difference between layers and tiers with nice pictures and nice list of pro/contra ) and wrapped in a new exception.

In the example above EnterpriseLibrary catches an exception and wraps it into another exception. Enterprise Library has an Exception Handling Application Block that lets you configure policies for your exceptions.
E.g. Handle “SQLException” globally, log and email the exception, then wrap it into “MyCustomException” depending of the property “SqlException.Errors”
That is something similar we did for System.Data.OracleClient.OracleException