Server Error in '/' Application.

An item with the same key has already been added.

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.ArgumentException: An item with the same key has already been added.

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:


[ArgumentException: An item with the same key has already been added.]
   System.ThrowHelper.ThrowArgumentException(ExceptionResource resource) +56
   System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) +13143720
   System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) +16
   Agora.Inscription.scfq2019.GetReservedStand(Int32 FormItemId) +650
   Agora.Inscription.scfq2019.Page_Init(Object sender, EventArgs e) +55
   System.Web.UI.Control.OnInit(EventArgs e) +79
   System.Web.UI.Page.OnInit(EventArgs e) +12
   System.Web.UI.Control.InitRecursive(Control namingContainer) +390
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1624


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4700.0