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POpopulate array list from For loop using entire database table row
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copied!<p>I am trying check my <code>Events</code> table for DateTime overlaps in each of the events. I have written code that will allow a user to input a <code>Module_code</code>. This <code>Module_code</code> is checked against the entries in the <code>Events</code> table. If <code>Start_Date_Time</code> or <code>End_Date_Time</code> for any of the events overlap with the <code>Start_Date_Time</code> or <code>End_Date_Time</code> of any other event in the table, for that module only, then I want to put the event row into an array list and later populate a gridview with the results. I have the following code, which I think achieves most of my goals. However when I run it the gridview there is no data in it. Debug shows that nothing was sent to it. I presume it is a problem with how I am trying to pass my values to the arrayList. </p> <pre><code> 'return all relevant tables from the Modules database, based on the module code entered by the user. Dim eventTime = (From mods In db.Modules Join evnt In db.Events On mods.Module_code Equals evnt.Module_code Join rm In db.Rooms On rm.Room_ID Equals evnt.Room_ID Join build In db.Buildings On build.Building_code Equals rm.Building_code Where ((mods.Module_code = initialModCode) And (evnt.Room_ID = rm.Room_ID)) Select evnt.Event_ID, evnt.Module_code, evnt.Event_type, evnt.Start_Date_Time, evnt.End_Date_Time, build.Building_code, rm.Room_Number) Dim listClashes As New ArrayList() For i As Integer = 0 To eventTime.Count - 1 For j As Integer = i + 1 To eventTime.Count - 1 If (eventTime.ToList(i).Start_Date_Time < eventTime.ToList(j).End_Date_Time) And (eventTime.ToList(i).End_Date_Time > eventTime.ToList(j).Start_Date_Time) Then 'MsgBox("Clash", MsgBoxStyle.MsgBoxSetForeground, "") listClashes.Add(eventTime) Else 'MsgBox("No Clash", MsgBoxStyle.MsgBoxSetForeground, "") End If Next Next gdvClashes.DataSource = listClashes gdvClashes.DataBind() </code></pre> <p>EDIT..Code changed to</p> <pre><code> If (eventTime(i).Start_Date_Time <= eventTime(j).End_Date_Time) And (eventTime(i).End_Date_Time >= eventTime(j).Start_Date_Time) Then 'MsgBox("Clash", MsgBoxStyle.MsgBoxSetForeground, "") listClashes.Add(eventTime.ToList) Else </code></pre> <p>This edit has not worked. It is throwing an exception to say that <code>The query operator 'ElementAtOrDefault' is not supported.</code> Am I going in the totally wrong direction here?</p> <p>EDIT..</p> <p>New code suggestion</p> <pre><code> Dim listClashes = From e1 In eventTime From e2 In eventTime Where (e2.Start_Date_Time >= e1.Start_Date_Time) And (e2.Start_Date_Time <= e1.End_Date_Time) Select eventTime gdvClashes.DataSource = listClashes gdvClashes.DataBind() </code></pre> <p>Should this be enclosed in a for loop or referencing an arrayList or something?</p>

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