"autocomplete" routine for combobox?
ben coats
i'm actually reposting this question, which i had up a
while back...
in MSAccess the combobox control had a property called
AutoComplete, which, when turned on, would fill the field
with the closest match from the list to whatever the user
was typing. the characters that the user had not yet
entered, but were from that matching item, were
highlited. i want to do something similar with some
combobox controls in vb.net. the thing is, i also want
the contents of the control to be checked against the
list and, if not in list, i want the user to be asked
whether they wish to add the item.
now, with the .DropDownStyle property of the combobox set
to DropDownList it will "complete" the text you are
entering with the closest match...however, when this is
set, you can ONLY select items from the list; you can't
enter items not in the list. if you set the property to
DropDown, then it will not "complete" your entry, but you
CAN add text not in the list. i need to find a happy
median, where i can do BOTH! i have comboboxes set to
DropDown, and have event methods written so that it will
check the contents and ask the user whether to add an
item not in the list, but what i want to know is, have
any of you written a method, or would know how to write
one, that would do the autocomplete thing for
you...something i could call (after a few validations)
from the TextChanged event?
any help on this would be greatly appreciated!!!
thanks!
ben
Programatix
Here's a simple sample I've written and used in my work,
Option Strict On
Imports System.ComponentModel
Public Class ComboBoxAutoComplete
Inherits System.Windows.Forms.ComboBox
Private m_isAutoCompleteSuspended As Boolean = False
Private m_strOriginal As String
#Region "Properties"
Private m_Autocomplete As Boolean = True
<Description("Enable or disable the autocomplete feature"),
Category("Behavior")> _
Public Property Autocomplete() As Boolean
Get
Return m_Autocomplete
End Get
Set(ByVal Value As Boolean)
m_Autocomplete = Value
If m_Autocomplete Then
Me.DropDownStyle = ComboBoxStyle.DropDown
End If
End Set
End Property
#End Region
#Region "Overrides"
Protected Overrides Sub OnTextChanged(ByVal e As System.EventArgs)
MyBase.OnTextChanged(e)
If Me.m_Autocomplete Then
If Not Me.m_isAutoCompleteSuspended Then
Dim index As Integer
Dim strlength As Integer
' Retrieve the current text's length
strlength = Me.Text.Length
' Try to find the match in the list
index = Me.FindString(Me.Text)
Try
If index > -1 Then
' A match is found. Select it.
Me.SelectedIndex = index
Me.SelectionStart = strlength
Me.SelectionLength = Me.Text.Length
End If
Catch
End Try
End If
End If
End Sub
Protected Overrides Sub OnKeyDown(ByVal e As
System.Windows.Forms.KeyEventArgs)
If Me.m_Autocomplete Then
Select Case e.KeyData
Case Keys.Back
If Me.SelectionStart > 0 Then
Me.SelectionStart -= 1
Me.SelectionLength += 1
Me.m_isAutoCompleteSuspended = True
End If
Case Keys.Escape
Me.m_isAutoCompleteSuspended = False
Me.Text = Me.m_strOriginal
Me.SelectAll()
Me.m_isAutoCompleteSuspended = True
Case Else
Me.m_isAutoCompleteSuspended = False
End Select
End If
MyBase.OnKeyDown(e)
End Sub
Protected Overrides Sub OnGotFocus(ByVal e As System.EventArgs)
If Me.m_Autocomplete Then
Me.m_strOriginal = Me.Text
End If
MyBase.OnGotFocus(e)
End Sub
Protected Overrides Sub OnLostFocus(ByVal e As System.EventArgs)
If Me.m_Autocomplete Then
Me.m_strOriginal = Nothing
End If
MyBase.OnLostFocus(e)
End Sub
Protected Overrides Sub OnValidating(ByVal e As
System.ComponentModel.CancelEventArgs)
If Me.m_Autocomplete Then
Dim index As Integer
If Me.Text = "" Then
Me.SelectedIndex = -1
Else
' Try to find the match in the list
index = Me.FindStringExact(Me.Text)
If index = -1 Then
' No match is found. Ask user whether to add it
Me.OnNoMatchFound(e)
Else
' A match is found. Select it
Me.SelectedIndex = index
End If
End If
End If
MyBase.OnValidating(e)
End Sub
#End Region
Public Delegate Sub NoMatchFoundEventHandler(ByVal sender As System.Object,
ByVal e As System.ComponentModel.CancelEventArgs)
Public Event NoMatchFound As NoMatchFoundEventHandler
Protected Overridable Sub OnNoMatchFound(ByVal e As
System.ComponentModel.CancelEventArgs)
RaiseEvent NoMatchFound(Me, e)
End Sub
End Class
"ben coats" <im4evri...@hotmail.com> wrote in message
news:016b01c2d6d3$dbd7c630$a601...@phx.gbl...
ben coats
ben
>