There are so many bugs in the template of "Time Track"

There are so many bugs in the template of "Time Track", an error occured while I want to try delete a project in the project list page.

Error meesage as follows:

Server Error in '/Sample' Application.

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Item has already been added. Key in dictionary: 'Id' Key being added: 'Id'

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: Item has already been added. Key in dictionary: 'Id' Key being added: 'Id'

Source Error:

Line 44: Protected Sub ListAllProjects_RowDeleting(ByVal sender As Object, ByVal e As GridViewDeleteEventArgs) Handles ListAllProjects.RowDeletingLine 45:Line 46: e.Keys.Add("Id", ListAllProjects.Rows(e.RowIndex).Cells(0).Text)Line 47: Line 48: End Sub

Source File:c:\inetpub\wwwroot\Sample\TimeTracker\Project_List.aspx.vb Line:46

Stack Trace:

[ArgumentException: Item has already been added. Key in dictionary: 'Id' Key being added: 'Id'] System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add) +2836739 System.Collections.Hashtable.Add(Object key, Object value) +11 System.Collections.Specialized.OrderedDictionary.Add(Object key, Object value) +49 Project_List_aspx.ListAllProjects_RowDeleting(Object sender, GridViewDeleteEventArgs e) in c:\inetpub\wwwroot\Sample\TimeTracker\Project_List.aspx.vb:46 System.Web.UI.WebControls.GridView.OnRowDeleting(GridViewDeleteEventArgs e) +133 System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow row, Int32 rowIndex) +604 System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +1155 System.Web.UI.WebControls.GridView.RaisePostBackEvent(String eventArgument) +199 System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +174 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5102

When you add a item to a HashTable you can't have the same key, in your case all items that will be added to your Hashtable will have the "Id" as a key, make sure the key value is unique.
I knew the database constraint. I just want to say the "Time Tracker" has many bugs. Because I have not change anything in the project list page and database object.