Collections or Hashtables

[spoiledkid]

From my DLL, I want to return some value in this format ...

test("Error",0)
test("Run",1)

and some more ....
which one should I use ... Collections or Hashtables ?

Also, right now I am returning hashtable from my DLL to form, and at the form side, I have declared a hashtable to take this return value in, but its always showing it as nothing for some reason, it returns the value from the DLL but on form side it becomes nothing automatically ????

[crptcblade]

Time to see some code.

[spoiledkid]

what code ? I just want to be able to return some keys and values associated with them ... I tried using array of System.Collections.DictionaryEntry, it worked. Just do not know which one is the preffered choice and why ?

[Bananafish]

The choice really depends on how you wish to access the data.

If it is to be more of a lookup table, ie you will be interrogating the data mainly by it's "key" value, or id you kust want to look at individual records based on the key value then I would suggest the hashtable.

If you mainly wish to retreive all the data every time with a for each...loop (for example) then the simple collection will be fine.

[spoiledkid]

Finally, I used Hashtables, work fine.

[Wokawidget]

What about a dataset?
When should u use either a collection, hashtable or a dataset?

Woof

[mendhak]

Originally posted by Wokawidget
What about a dataset?
When should u use either a collection, hashtable or a dataset?

Woof

That's a little overboard. DataSets would be most suited when working with a database or an XML data source.

I guess a hashtable is just like a collection, excepting that it is faster to search in.

[spoiledkid]

Originally posted by Wokawidget
What about a dataset?
When should u use either a collection, hashtable or a dataset?

Woof

Yes, mendhak is right, dataset will be more like a overhead in this situation. Hashtables are just like collections, only they are better (I think) as far as speed is concerned.

[Wokawidget]

So you would use these in the UI and not in the backend to pass data back to the UI???

Eh?

When running .NET and I come to a break point in my code, why can't I see the form1? As soon as it goes into the .NET IDE then the active form goes all white and I can't see anything on it.
Is this correct? Bad .NET IDE *slap*

[spoiledkid]

Originally posted by Wokawidget
So you would use these in the UI and not in the backend to pass data back to the UI???

Eh?

When running .NET and I come to a break point in my code, why can't I see the form1? As soon as it goes into the .NET IDE then the active form goes all white and I can't see anything on it.
Is this correct? Bad .NET IDE *slap*

I have written a generic DLL component for Data Access with SQL Server based on Microsoft Standards and best practices. Now, there is this function called ExecuteStoredProcedure. This is a overloaded SP and can return either DataSet or DataTable for the results of a SP. But if SP has some output parameters too, then I need a way to return those Output paramters/values to UI too. They can not be part of DataSet or DataTable.

So I did something like this ...

ExecSP(ObjectToReturn as Object, blah blah) as Hashtable

if typename(ObjectToReturn ) is Dataset then return dataset
if typename(ObjectToReturn ) is Datatable then return Datatable

for each output parameter and if there is an @RETURN_VALUE parameter from SP too, I built a hashtable, add all those things to hashtable with there name, add one more item called "Error" pass it 0 if there was successfully execution of SP otherwise pass 1. This way my UI can not only get the SP data but also output parameters (if there were any).

[spoiledkid]

Here's one method code ..

Public Overloads Function ExecuteStoredProcedure(ByVal connection As SqlConnection, ByVal storedProcedureName As String, _
                                                     ByRef returnObject As Object, ByVal sqlParameters() As SqlParameter, _
                                                     Optional ByVal includeReturnValue As Boolean = True, _
                                                     Optional ByVal mustCloseConnection As Boolean = False) As Hashtable
        Dim i, j As Int16
        Dim dataAdapter As New SqlDataAdapter
        Dim returnValues As New Hashtable(New CaseInsensitiveHashCodeProvider, New CaseInsensitiveComparer)
 
        Try
            OpenConnection(connection)
 
            Dim command As New SqlCommand(storedProcedureName, connection)
            command.CommandType = CommandType.StoredProcedure
 
            If Not (sqlParameters Is Nothing) Then
                For i = 0 To CType(sqlParameters.Length - 1, Short)
                    command.Parameters.Add(sqlParameters(i))
                Next
            End If
 
            If includeReturnValue Then
                Dim returnValue As New SqlParameter("@RETURN_VALUE", SqlDbType.BigInt)
                returnValue.Direction = ParameterDirection.ReturnValue
                command.Parameters.Add(returnValue)
            End If
 
            dataAdapter.SelectCommand = command
 
            If TypeName(returnObject).ToUpper = ("DataSet").ToUpper Then
                dataAdapter.Fill(CType(returnObject, DataSet))
            ElseIf TypeName(returnObject).ToUpper = ("DataTable").ToUpper Then
                dataAdapter.Fill(CType(returnObject, DataTable))
            Else
                command.ExecuteNonQuery()
                returnObject = Nothing
            End If
 
            returnValues.Add("Error", 0)
 
            If includeReturnValue Then
                returnValues.Add("@RETURN_VALUE", command.Parameters("@RETURN_VALUE").Value)
            End If
 
            Dim sqlParameter As SqlParameter
 
            For Each sqlParameter In command.Parameters
                If sqlParameter.Direction = ParameterDirection.InputOutput Or sqlParameter.Direction = ParameterDirection.Output Then
                    returnValues.Add(sqlParameter.ParameterName.ToString, sqlParameter.Value)
                End If
            Next
 
            Return (returnValues)
 
        Catch sqlex As SqlException
 
            returnValues.Add("Error", 1)
            LogException(sqlex)
 
        Catch ex As Exception
 
            returnValues.Add("Error", 1)
            LogException(ex)
 
        Finally
            dataAdapter.Dispose()
            If mustCloseConnection Then CloseConnection(connection)
        End Try
    End Function