AutoComplete ComboBox in VB.Net

Introduction

This is an AutoCompleting ComboBox that works with Data Bound or Regular ComboBoxes in VB.NET. As you type the case is preserved but the remaining text is auto filled by the list items. When the Leave function is called the case is fixed and the index from the list is also selected if there is a matching item.

Call the corresponding functions from your Combobox's KeyUp and Leave events like so:

Private Sub cboName_Leave(ByVal sender As Object, ByVal e As System.EventArgs) 
                                                            Handles cboName.Leave
    Dim recRowView As DataRowView
    Dim recName As DB.tblNameRow

    AutoCompleteCombo_Leave(cboName)

    'OPTIONAL: Now you can  do some extra handling if you want


    'Get the Selected Record from my Data Bound Combo (Return Type is DataRowView)

    recRowView = cboName.SelectedItem
    If recRowView Is Nothing Then Exit Sub

    'Display the Name Info (Row Type comes from my bound Dataset)

    recName = recRowView.Row
    lblAccountNum.Text = recName.AccountNum
    lblCompanyName.Text = recName.CompanyName

End Sub

Private Sub cboName_KeyUp(ByVal sender As Object, 
              ByVal e As System.Windows.Forms.KeyEventArgs) Handles cboName.KeyUp

    AutoCompleteCombo_KeyUp(cboName, e)

End Sub

Here are the Generic Functions for handling the events:

Public Sub AutoCompleteCombo_KeyUp(ByVal cbo As ComboBox, ByVal e As KeyEventArgs)
    Dim sTypedText As String
    Dim iFoundIndex As Integer
    Dim oFoundItem As Object
    Dim sFoundText As String
    Dim sAppendText As String

    'Allow select keys without Autocompleting

    Select Case e.KeyCode
        Case Keys.Back, Keys.Left, Keys.Right, Keys.Up, Keys.Delete, Keys.Down
            Return
    End Select

    'Get the Typed Text and Find it in the list

    sTypedText = cbo.Text
    iFoundIndex = cbo.FindString(sTypedText)

    'If we found the Typed Text in the list then Autocomplete

    If iFoundIndex >= 0 Then

        'Get the Item from the list (Return Type depends if Datasource was bound 

        ' or List Created)

        oFoundItem = cbo.Items(iFoundIndex)

        'Use the ListControl.GetItemText to resolve the Name in case the Combo 

        ' was Data bound

        sFoundText = cbo.GetItemText(oFoundItem)

        'Append then found text to the typed text to preserve case

        sAppendText = sFoundText.Substring(sTypedText.Length)
        cbo.Text = sTypedText & sAppendText

        'Select the Appended Text

        cbo.SelectionStart = sTypedText.Length
        cbo.SelectionLength = sAppendText.Length

    End If

End Sub


Public Sub AutoCompleteCombo_Leave(ByVal cbo As ComboBox)
    Dim iFoundIndex As Integer

    iFoundIndex = cbo.FindStringExact(cbo.Text)

    cbo.SelectedIndex = iFoundIndex

End Sub

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Thank you Zestelle 6:02 16 Sep '09   I'm new to VB.Net and I found it surprising that this kind of behavior was not built in the basic combobox control?! So thank you very much for the code, I found it really helpful. It works exactly as I wanted. Zestelle Sign In·View Thread·PermaLink 1.00/5 (1 vote) Problem in Access database query Ayesha.Hafeez 6:35 16 Dec '08   I am receiving problem like sysntax error in INSERT INTO statement. I checked it again n again but I am unable to find eror in this code segment if anyone can help i will appeciate their concern. code segment is cmd = New OleDbCommand("INSERT INTO Transaction VALUES('" & WithDrawTxt.Text & "','" & AccountNo.ToString & "','" & dt.ToString & "')", cn) i = cmd.ExecuteNonQuery Table INFO Table Transaction has fields Amount, Account_Number, Transaction_Date and last is Transaction#. All have field text except Transaction# which is auto number. Sign In·View Thread·PermaLink Re: Problem in Access database query bwarehouse 17:01 23 Feb '09   MS Access rejects some non-alphanumeric characters like ' (apostrophe), if not formatted properly. Try this: cmd = New OleDbCommand("INSERT INTO Transaction VALUES('" & WithDrawTxt.Text.Replace("'","''") & "', '" & AccountNo.ToString & "', '" & dt.ToString & "')", cn). Also, for inserting numbers into MS Access Database, you may find it easier if you set the "AccountNo" field in the database to "Number", instead of "Text". This way, you can remove the ' (apostrophes) surrounding your number in the sql string ('" & AccountNo.ToString & "','"). If you do change the MS Access field type to "Number", the sql string should look like this: cmd = New OleDbCommand("INSERT INTO Transaction VALUES('" & WithDrawTxt.Text.Replace("'","''") & "', " & AccountNo & ", '" & dt.ToString & "')", cn). One last observation; I don't know what format "dt" is in, but if you have the MS Access field set to "DateTime", and you are attempting to send it a string value (dt.ToString)(if dt is a date in string format), then that will fail every time. If dt.ToString is in some type of "date/datetime" format, you have to enclose the value with the # (pound sign), like this: ...,'" & AccountNo.ToString & "', #" & dt.ToString & "#)", cn) Hope this helps. b.ware, A.P.W.S (A programmer without sleep) b.ware, A.P.W.S (A programmer without sleep) Sign In·View Thread·PermaLink Autocomplete Question mchlcmprch 14:29 29 Oct '07   I seem to be (as usual) confused by the behaviour of autocomplete combos. Is it my imagination or do autocomplete combos change their selected indexes when they are selected? I have an app where this seems to be happening... a little background... On a winform I have three combos all populated from the same arraylist.A concept number, an item number and a name, all related and associated. there are occasions when, for instance, I have set the selectedindex to, say 122, via selecting a concept number, and when I click or tab to the next combo, the selected indexes seem to be set to 0! Very irritating. This is definately in some way due to autocomplete, because if I make them all autocomplete false this doesn't happen. Unfortunately there is a reqirement for autocomplete.... I'm really frustrated and all my googling has not yet gotten me an solution! Michael S. Comperchio michael.comperchio@hotmail.com 203 218 4053 Sign In·View Thread·PermaLink Autocomplete suggestion must try.. Samee Dars 23:44 16 Mar '08   please try following properties to enable autocomplete feature for combo box... set theese properties form property window... cb.AutoCompleteSource=ListItems //there are other options also... cb.AutoCompleteMode=SuggestAppend //there are differnets modes available u can try them also.... for code try this.... this.cb.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.SuggestAppend; this.cb.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems; [$@^^€€] Sign In·View Thread·PermaLink Re: Autocomplete suggestion Samee Dars 23:58 16 Mar '08   sorry there that feature works in 2.0 [$@^^€€] Sign In·View Thread·PermaLink Re: Autocomplete suggestion dibblm-Ohio 6:31 9 Jan '09   Its works for me. thank you soooooo much. Im a fairly novice programmer and I dont know how to state what Im looking for. I ran into the original post. Saw all the code he had to go through and decided to see if someone had modified it any when I ran into your post. Works like a charm. Only the page flutters a couple time after you select a record. Any idea why ? Mike Dibble Sign In·View Thread·PermaLink thank ansing 4:31 20 Jan '07   i find the code very helpful for a beginner like me....thanks more power knowlege is a treasure but practice is the key Sign In·View Thread·PermaLink thank ansing 4:30 20 Jan '07   knowlege is a treasure but practice is the key Sign In·View Thread·PermaLink DroppedDown andrewf22 12:16 11 Jan '07   If you use DroppedDown=true to make the combo behave like an IE autocomplete combobox the combox shows the selected text but when you try to get it through code for ex: combobox.Text or combobox.SelectedIndex point to the previous selection. Any one figure out how to get around this issue ???? Sign In·View Thread·PermaLink 2.00/5 (1 vote) Re: DroppedDown paulmcl 4:17 26 Jan '07   I have the same problem and can't pin down where its going wrong. Until yesterday i thought my users were going mad reporting very intermittent problems, I wont say anything about my testing... Seems to me that the updated value is definitely being saved but then overriden with the old value somewhere, eg as soon as we enter the leave event the old value is back. I've had a look through the events and properties but cant see anything you need to set to persist the value, eg like the way you handle the key events. In the end I've had to resort to using a temporary form level object to store the autocomplete value of the combobox and a flag to indicate whether our autocomplete code has been used. in the leave event if flag == true point the combobox to the temporary object and reset the flag to false. I really dont like to do this as its a very bad solution so if anyone has a proper way i'd love to know. paulmcl Sign In·View Thread·PermaLink 2.00/5 (1 vote) Re: DroppedDown sephus6 12:24 15 Dec '08   I've ran into problems when I tried to type in more than one character for the autocomplete. My solution was to add this code to the Leave event of the combo box: Me.SelectionStart = 0 Me.SelectionLength = Me.Text.Length - Me.SelectionStart That fixed the 'SelectedText' property, but for some reason when the LostFocus method fires the selected index gets reset, even though the text of the combo box is still correct. To fix this I added the following code to the LostFocus event of the combo box: Me.SelectedIndex = Me.FindStringExact(Me.Text) Hope this helps. -S Sign In·View Thread·PermaLink A little different code rtodosic 8:15 31 Mar '06   After looking at your code, and then looking at some of my old Delphi code. I found that the following code worked a little better for me. Just thought I would share (Sorry about the C# code) private void comboBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e) { _lastKey = e.KeyCode; } private void comboBox1_TextChanged(object sender, System.EventArgs e) { ComboBox cbo = (ComboBox) sender; string srch = cbo.Text; if (_lastKey == Keys.Back || _lastKey == Keys.Delete || _lastKey == Keys.None) { _lastKey = Keys.None; return; } _lastKey = Keys.None; int idx = cbo.FindString(@srch); if (idx != -1) { cbo.SelectedIndex = idx; cbo.SelectionStart = srch.Length; cbo.SelectionLength = cbo.Text.Length - srch.Length; } } private void comboBox1_Leave(object sender, System.EventArgs e) { ComboBox cbo = (ComboBox) sender; cbo.SelectedIndex = cbo.FindStringExact(cbo.Text); if (cbo.SelectedIndex == -1) cbo.Text = string.Empty; _lastKey = Keys.None; } Sign In·View Thread·PermaLink 1.00/5 (1 vote) Re: A little different code (vb.net version instead of c#) bwarehouse 21:40 23 Feb '09   * Private Sub comboBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) * _lastKey = e.KeyCode * End Sub * * Private Sub comboBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) * Dim cbo As ComboBox = DirectCast(sender, ComboBox) * Dim srch As String = cbo.Text * * If _lastKey = Keys.Back OrElse _lastKey = Keys.Delete OrElse _lastKey = Keys.None Then * _lastKey = Keys.None * Exit Sub * End If * _lastKey = Keys.None * Dim idx As Integer = cbo.FindString(srch) * If idx <> -1 Then * cbo.SelectedIndex = idx * cbo.SelectionStart = srch.Length * cbo.SelectionLength = cbo.Text.Length - srch.Length * End If * End Sub * * Private Sub comboBox1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) * Dim cbo As ComboBox = DirectCast(sender, ComboBox) * cbo.SelectedIndex = cbo.FindStringExact(cbo.Text) * If cbo.SelectedIndex = -1 Then * cbo.Text = String.Empty * End If * _lastKey = Keys.None * End Sub b.ware Sign In·View Thread·PermaLink only works when I type slowly miko_tnt 6:20 21 Nov '05   Hi mfs ... I saw this code few days ago and i use it, i also read the mesages all of u post to see how it works. My problem ocurred when i wrote quickly. I put the class that inherit the combobox taht one of u post but it didn't solve my problem. i can write fast and it capture all the characters i want, but when i wrote the first character that change the word and it isnt in my combo the cursor pass to the last position (max length) and i continue writting there, so it leave a lot of blank spaces, but if i type slowly it doesnt happend, i can continue typing after the last char. I hope u undertood my question and can solve ir .. thx Pd .. sry 4 my english Sign In·View Thread·PermaLink 1.00/5 (1 vote) What is DB.tblNameRow? sanders.tec 8:53 16 Sep '05   I don't see a reference for DB in this example! Sign In·View Thread·PermaLink 1.00/5 (3 votes) Re: What is DB.tblNameRow? Johann Lazarus 14:00 2 Feb '09   Did you get a reply to this or were you able or figure it out? I'm trying to replicate this in C#. Sign In·View Thread·PermaLink 1.00/5 (1 vote) needs improvement eletters_my 20:48 30 Jan '05   nice attempt but needs improvement 9891965160 developer.nettechnologies@gmail.com Sign In·View Thread·PermaLink 1.00/5 (1 vote) autofill only works when I type slow Robert Gray 15:59 20 Jun '04   The above code is great, for slow typers. I found that when I type quickly in the combo box, it doesn't find the correct entry. When I type the same thing slowly, everything works fine. any ideas on how to get around this problem? I've looked at various alorithms (mostly very similar variants) for autofill and it seems that all would have this problem. Never had this problem on custom autofill routines on data bound controls in Vb6. Sign In·View Thread·PermaLink Re: autofill only works when I type slow Joseph Hicks 13:27 27 Jan '05   I've had this problem in the past as well.   I found that the problem would be when a 2nd (or 3rd, 4th, etc.) key was pressed before the first key was released.   This wouldn't be an issue for someone with only one finger, but for the rest of us my solution is as follows. Declaration of my control: Public Class AutoFillComboBox       Inherits ComboBox First add a private data member to store the most recent keydown key: Private _LastKeyDown As System.Windows.Forms.KeyEventArgs In the KeyDown event of my object, I'll store the key that was pressed: Protected Overrides Sub OnKeyDown(ByVal e as System.Windows.Forms.KeyEventArgs)       MyBase.OnKeyDown(e)       _LastKeyDown = e End Sub And finally, the first thing I do in the KeyUp event is to ensure that the key that was released was actually the last key pressed (ie: ignore the KeyUp unless it was also the last KeyDown).   Also, a key may have been held down before the control was loaded, so if the last KeyDown doesn't exist (Is Nothing), ignore that too: Protected Overrides Sub OnKeyUp(ByVal e as System.Windows.Forms.KeyEventArgs)       MyBase.OnKeyUp(e)       If (_LastKeyDown Is Nothing) = True OrElse (e.KeyCode = _LastKeyDown.KeyCode) = False Then Exit Sub       ....... processing to AutoComplete ....... End Sub I'm sure that using overrides is unnecessary, and you could probably just store the e.KeyCode value in a System.Windows.Forms.Keys variable, but that's not the point.    Hope this helps someone out there in the future... Joseph Hicks jhicks<AT>ifmc.org Sign In·View Thread·PermaLink 5.00/5 (2 votes) Re: autofill only works when I type slow Tunca Bergmen 4:07 3 Feb '05   This works great. Thanks Tunca Bergmen Sign In·View Thread·PermaLink Re: autofill only works when I type slow Anonymous 7:19 14 Apr '05   Could you please leave complete code for inherited class, I'm having problems here Sign In·View Thread·PermaLink Save Combo Box ukjock 8:34 1 Jan '04   Can anybody suggest and easy and efficent way to save the contents of the combobox and when a form is reloaded, The data brought back in to the combobox. I have tried to use this code, and it works great. But I am having difficulty saving all the data and reloading it. Any help appreciated. Thanks Chris Sign In·View Thread·PermaLink 3.00/5 (3 votes) Re: Save Combo Box dELm 16:22 5 Feb '04   1- databases (mysql, msqls, etc) -> if you are working with large amounts of complex data... 2- XML -> save/load to/from a xml file. 3- ini -> save/load to/from a ini file. if you want more info about these files, search in this same site. Sign In·View Thread·PermaLink 2.00/5 (4 votes) Re: Save Combo Box aniepras 8:24 30 Dec '04   easiest way is to use a database Sign In·View Thread·PermaLink 1.00/5 (1 vote)

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