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Getting a Key (the String value) out of a HashTable

Friends,

Okay, I am trying to get the String Value of a key out of a HashTable, so that I can find if it needs to be removed.

Here is the For Loop that I have created, and the logic with it. I need to know what needs to be inserted where the ??? marks are, please.

For Each DriverEntrantHT.??? In DriverEntrantHT

SearchOnKey = DriverEntrantHT.??? 'The String Value of the Key
SplitUpKey = Split(SearchOnKey, "-")

DriverEntrantHT_CarNumberTemp = SplitUpKey(0)
DriverEntrantHT_FirstNameTemp = SplitUpKey(1)
DriverEntrantHT_LastNameTemp = SplitUpKey(2)

If e_CarNumber = DriverEntrantHT_CarNumberTemp And _
((e_Driver_FirstName = DriverEntrantHT_FirstNameTemp) Or (e_Driver_FirstName = DriverEntrantHT_FirstNameTemp)) Then
DriverEntrantHT.Remove(SearchOnKey)
Else
DriverEntrantKey = (e_CarNumber & "-" & e_Driver_FirstName & "-" & e_Driver_LastName)

DriverEntrantProperty.FirstName = e_Driver_FirstName
DriverEntrantProperty.LastName = e_Driver_LastName
' Add info to Hashtable
DriverEntrantHT.Add(DriverEntrantKey, DriverEntrantProperty)
End If

Next

Thanks in advance!
Regards,
Eric

If you would like to see the rest of the code, and where this for loop is in the code, it is below:

Dim DriverEntrantHT As New Hashtable
Dim oDriverEntrant As DriverEntrant

Public Sub ProcessValidString(ByVal AMBMLPValidString As String) 'Handles RecieveValidAMBMLPString.ValidAMBMLPString

Dim SplitUpString() As String
SplitUpString = Split(AMBMLPValidString, "¦")

If SplitUpString.GetUpperBound(0) = 0 Then
Exit Sub
End If

Dim Record As String
Record = SplitUpString(0)
'Split()
Dim CarNumberKey As Integer

Dim RecordType As String
RecordType = SplitUpString(1)

Dim DriverEntrantKey As String = Nothing
Select Case Record

Case "E"

Dim DriverEntrantProperty As New DriverEntrant

If RecordType = "N" Or "R" Then
'If CarNumber doesn't exist in array, add (3) values to array as record
e_CarNumber = AMBParser_Entrant.GetValue(AMBMLPValidString, 4) 'Just know that this returns the CarNumber of this particular record...
e_Driver_FirstName = AMBParser_Entrant.GetValue(AMBMLPValidString, 61)
e_Driver_LastName = AMBParser_Entrant.GetValue(AMBMLPValidString, 62)

DriverEntrantKey = (e_CarNumber & "-" & e_Driver_FirstName & "-" & e_Driver_LastName)

CarNumberExistsInList = False
If DriverEntrantHT.ContainsKey(DriverEntrantKey) Then
CarNumberExistsInList = True
End If

If CarNumberExistsInList = False Then

DriverEntrantProperty.FirstName = e_Driver_FirstName
DriverEntrantProperty.LastName = e_Driver_LastName

' Add info to Hashtable
DriverEntrantHT.Add(DriverEntrantKey, DriverEntrantProperty)

End If

ElseIf RecordType = "U" Then

Dim SearchOnKey As String
Dim SplitUpKey() As String

Dim DriverEntrantHT_CarNumberTemp As String
Dim DriverEntrantHT_FirstNameTemp As String
Dim DriverEntrantHT_LastNameTemp As String

e_CarNumber = AMBParser_Entrant.GetValue(AMBMLPValidString, 4) 'Just know that this returns the CarNumber of this particular record...
e_Driver_FirstName = AMBParser_Entrant.GetValue(AMBMLPValidString, 61)
e_Driver_LastName = AMBParser_Entrant.GetValue(AMBMLPValidString, 62)

For Each DriverEntrantHT.??? In DriverEntrantHT 'This is the aforementioned for loop !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

SearchOnKey = DriverEntrantHT.???
SplitUpKey = Split(SearchOnKey, "-")

DriverEntrantHT_CarNumberTemp = SplitUpKey(0)
DriverEntrantHT_FirstNameTemp = SplitUpKey(1)
DriverEntrantHT_LastNameTemp = SplitUpKey(2)

If e_CarNumber = DriverEntrantHT_CarNumberTemp And _
((e_Driver_FirstName = DriverEntrantHT_FirstNameTemp) Or (e_Driver_FirstName = DriverEntrantHT_FirstNameTemp)) Then
DriverEntrantHT.Remove(SearchOnKey)
Else
DriverEntrantKey = (e_CarNumber & "-" & e_Driver_FirstName & "-" & e_Driver_LastName)

DriverEntrantProperty.FirstName = e_Driver_FirstName
DriverEntrantProperty.LastName = e_Driver_LastName
' Add info to Hashtable
DriverEntrantHT.Add(DriverEntrantKey, DriverEntrantProperty)
End If

Next

End If

ASKER CERTIFIED SOLUTION

ZeonFlash

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indy500fan

ASKER

ZeonFlash,

With regards to the first example what would i set SearchOnKey equal to?

For Each DriverEntrant as DictionaryEntry

SearchOnKey = DriverEntrantHT.???

Thanks,

Eric

indy500fan

ASKER

SearchOnKey = DriverEntrant.ToString ???

ZeonFlash

The DictionaryEntry data type has the properties Key and Value, which are the same properties you used to create the entry in the hashtable. So you would use:

For Each DriverEntrant as DictionaryEntry In DriverEntrantHT

SearchOnKey = DriverEntrant.Key

indy500fan

ASKER

Ah, thanks ZeonFlash!

Fernando Soto

Hi indy500fan;

I went through the first part of the code, to remove an Item from the HashTable. The code now has the correct syntax but has a logic error in it.

1. To be able to remove an item from the HashTable the collection of items cannot be in use. In other words you can not use the DriverEntrantHT in the for statement to get a copy of an object in the HashTable. So we need to make a copy of the DriverEntrantHT and use that.

2. The logic error, if the values in e_Driver_FirstName, e_CarNumber and e_Driver_LastName do not change in each iteration of the loop then one part of the if statement will remove and entry and on the next loop will add it back but then if there are any entries left in the HashTable the next loop will throw an error because it will try to add it again and that is not allowed.

Dim TempHT As Hashtable = CType(DriverEntrantHT.Clone, Hashtable)
For Each obj As DictionaryEntry In TempHT
SplitUpKey = Split(obj.Key.ToString(), "-")

DriverEntrantHT_CarNumberTemp = SplitUpKey(0)
DriverEntrantHT_FirstNameTemp = SplitUpKey(1)
DriverEntrantHT_LastNameTemp = SplitUpKey(2)

If e_CarNumber = DriverEntrantHT_CarNumberTemp And _
((e_Driver_FirstName = DriverEntrantHT_FirstNameTemp) Or _
(e_Driver_FirstName = DriverEntrantHT_FirstNameTemp)) Then
DriverEntrantHT.Remove(obj.Key.ToString())
Else
DriverEntrantProperty = New DriverEntrant
DriverEntrantKey = (e_CarNumber & "-" & e_Driver_FirstName & _
"-" & e_Driver_LastName)
DriverEntrantProperty.CarNumber = e_CarNumber
DriverEntrantProperty.FirstName = e_Driver_FirstName
DriverEntrantProperty.LastName = e_Driver_LastName
' Add info to Hashtable
DriverEntrantHT.Add(DriverEntrantKey, DriverEntrantProperty)
End If
Next

Fernando

indy500fan

ASKER

Thanks Fernando. I've added it into my code, and as soon as I can get my Event Handles, Handler, etc. working, I can test this!