Server Error in '/' Application.

Sequence contains more than one matching element

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Sequence contains more than one matching element

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[InvalidOperationException: Sequence contains more than one matching element]
   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source, Func`2 predicate) +4919592
   Ssgf.Web.TreeNodeBase.GetChild(String key) in D:\rbobik\Ssgf\Ssgf.Web\TreeNodeBase.cs:50
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:113
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:118
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:118
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:118
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:118
   Simpage.Web.TreeNodeExtensions.GetNode(ITreeNode context, String relativePath) in D:\rbobik\Simpage\Web\TreeNode.cs:118
   Simpage.Web.HttpHandler.ProcessRequest(HttpContext context) in D:\rbobik\Simpage\Web\HttpHandler.cs:98
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +195
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +50
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +73


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4690.0