"Armin Zingler" <az.nospam@freenet.de> wrote in message
news:eBh5SJa1JHA.4272@TK2MSFTNGP06.phx.gbl...
> Rob W wrote:
>> Any ideas how I make the process more efficient to populate a combo
>> box with 40,000 + items?
>
> How fast do you expect it? The following code takes 1.7 seconds: (40,000
> lines, each 30 characters, Athlon64 X2 4400+ 2.2GHz)
>
> Me.ComboBox1.Items.AddRange( _
>    IO.File.ReadAllLines("e:\test.txt", System.Text.Encoding.Default) _
> )
>
>
> Armin

> Greetings,
>
> The vb.net application I'm developing is for data input and have utilised a
> combo box which is populated with a list of UK towns.
>
> As it is 40,000 lines long I have recently had problems testing the
> application as it doesn't always run when using the standard F5 - Start
> debugging a problem which doesn't occur when I removed the code to populate
> the combox box.
>
> It is a lot of records to scroll through, but wtih the suggestive text input
> only 2-3 characters are usally needed until your town is a click away.
>
> Thinking maybe its to ambitious to populate with 40,000 items.
>
>
>
> Code below populates the combo box:-
>
> 'StreamReader to read towns from a text file
>
> Dim townfile As New System.IO.StreamReader(Application.StartupPath +
> "\towns.txt", System.Text.Encoding.Default)
>
>
>
> ' Read file until no more data exists . i.e. BLANK LINE found
>
> Do While townfile.Peek <> -1
>
>     Dim LineIn As String = townfile.ReadLine()
>
>     cboTown.Items.Add(LineIn)
>
> Loop
>
>
>
> I did look at other solutions like loading the data into an Array,
> Stringbuilder, list and looking at I could use a buffer somehow.
>
> I did try to use an 1d string array and use the streamReader ReadtoEnd
> mnethod but I couldn't get the conversion types right :-(
>
> Any ideas how I make the process more efficient to populate a combo box with
> 40,000 + items?
>
>
>
> Cheers
>
> Rob
>
>

"Mike" <unkn***@unknown.tv> wrote in message
news:ezzXtwa1JHA.5684@TK2MSFTNGP04.phx.gbl...
> See if using VIRTUAL LIST controls features is possible, where you tell
> the list control the bounds and it will issue an callback with a index to
> the view port for the amount you want to show per page.
>
> I'm new to .NET but Virtual list controls  have been been part of the
> Windows GUI tools library since MFC specifically design to handle large
> list data needs.
>
> I'm sure the VB.NET class have incorporated the same needs. If directly,
> you can always do owner drawn controls.
>
> Search for:
>
>     virtual list controls for .NET
>
> --
>
>
>
> Rob W wrote:
>> Greetings,
>>
>> The vb.net application I'm developing is for data input and have utilised
>> a combo box which is populated with a list of UK towns.
>>
>> As it is 40,000 lines long I have recently had problems testing the
>> application as it doesn't always run when using the standard F5 - Start
>> debugging a problem which doesn't occur when I removed the code to
>> populate the combox box.
>>
>> It is a lot of records to scroll through, but wtih the suggestive text
>> input only 2-3 characters are usally needed until your town is a click
>> away.
>>
>> Thinking maybe its to ambitious to populate with 40,000 items.
>>
>>
>>
>> Code below populates the combo box:-
>>
>> 'StreamReader to read towns from a text file
>>
>> Dim townfile As New System.IO.StreamReader(Application.StartupPath +
>> "\towns.txt", System.Text.Encoding.Default)
>>
>>
>>
>> ' Read file until no more data exists . i.e. BLANK LINE found
>>
>> Do While townfile.Peek <> -1
>>
>>     Dim LineIn As String = townfile.ReadLine()
>>
>>     cboTown.Items.Add(LineIn)
>>
>> Loop
>>
>>
>>
>> I did look at other solutions like loading the data into an Array,
>> Stringbuilder, list and looking at I could use a buffer somehow.
>>
>> I did try to use an 1d string array and use the streamReader ReadtoEnd
>> mnethod but I couldn't get the conversion types right :-(
>>
>> Any ideas how I make the process more efficient to populate a combo box
>> with 40,000 + items?
>>
>>
>>
>> Cheers
>>
>> Rob
>>