Implementing the IAutoComplete2 Interface in Vb.Net

[dynamic_sysop]

I've been teaching myself a bit about Interfaces for a little while and decided to try to create a vb.net version of the IAutoComplete2 interface.

you can see info on this for C++ on msdn.

this example implements autocomplete on an given array of strings ( eg: in a listbox , combobox etc... )

   Private autoComp As AutoComplete

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       '/// add autocomlete to an array of strings, in this case a listbox
       autoComp = New AutoComplete(TextBox1.Handle, ArrayList.Adapter(ListBox1.Items))
       '/// enable autocomplete
       autoComp.Enable()

   End Sub
End Class

#Region " AutoComplete Class "

Public Class AutoComplete
   Implements IDisposable

   Private autoComp As Type
   Private objAutoComp As IAutoComplete

   Public Sub New(ByVal hwndEdit As IntPtr, ByVal strList As ArrayList, Optional ByVal pwszRegKeyPath As String = Nothing, Optional ByVal pwszQuickComplete As String = Nothing)
       Dim iEnumList As New EnumString()
       iEnumList.strArray = strList

       autoComp = Type.GetTypeFromCLSID(New Guid("{00BB2763-6A77-11D0-A535-00C04FD7D062}"))
       objAutoComp = DirectCast(Activator.CreateInstance(autoComp), IAutoComplete)

       '/// initialize IAutoComplete
       objAutoComp.Init(hwndEdit, iEnumList, pwszRegKeyPath, pwszQuickComplete)
       '/// set IAutoComplete Options
       objAutoComp.SetOptions(Convert.ToUInt32(ShowOptions.ACO_AUTOSUGGEST Or ShowOptions.ACF_UPDOWNKEYDROPSLIST Or ShowOptions.ACO_AUTOAPPEND))
       '/// Enable IAutoComplete
       objAutoComp.Enable(True)

   End Sub

   Public Sub Dispose() Implements System.IDisposable.Dispose
       Me.ReleaseComObject = Marshal.ReleaseComObject(objAutoComp)
   End Sub

   Private WriteOnly Property ReleaseComObject()
       Set(ByVal Value)
           Me.ReleaseComObject = Value
       End Set
   End Property

   Public Sub Disable()
       objAutoComp.SetOptions(Convert.ToUInt32(ShowOptions.ACO_NONE))
   End Sub

   Public Sub Enable()
       objAutoComp.SetOptions(Convert.ToUInt32(ShowOptions.ACO_AUTOSUGGEST Or ShowOptions.ACF_UPDOWNKEYDROPSLIST Or ShowOptions.ACO_AUTOAPPEND))
   End Sub

End Class

#End Region


#Region " IAutoComplete2 Interface "

<ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("EAC04BC0-3791-11D2-BB95-0060977B464C")> _
Public Interface IAutoComplete

   Function Init(ByVal hwndEdit As IntPtr, <MarshalAs(UnmanagedType.IUnknown)> ByVal punkACL As Object, ByVal pwszRegKeyPath As String, ByVal pwszQuickComplete As String) As Int32
   '/// we must use <PreserveSig()> _ otherwise after using autocomplete , fields will not return the next time
   <PreserveSig()> _
   Function Enable(<[in]()> ByVal fEnable As Boolean) As Boolean
   <PreserveSig()> _
   Function SetOptions(<[in]()> ByVal dwFlag As UInt32) As Integer
   <PreserveSig()> _
   Function GetOptions(<Out()> ByRef pdwFlag As UInt32) As Integer

End Interface

#End Region

#Region " IEnumString Interface "
'/// HKEY_CLASSES_ROOT\Interface\{00000101-0000-0000-C000-000000000046}\IEnumString
<ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("00000101-0000-0000-C000-000000000046")> _
Public Interface IEnumString

   Function [Next](ByVal celt As Integer, ByVal rgelt() As String, ByRef pceltFetched As Integer) As Integer
   Function Skip(ByVal celt As Integer) As Integer
   Function Reset() As Integer
   Sub Clone(ByRef ppenum As IEnumString)

End Interface

#End Region

#Region " IEnumString Class "

Public Class EnumString
   '/// UCOMIEnumString is the same as the IEnumString interface
   '/// see more at Msdn on [url]http://msdn.microsoft.com/library/default.asp?url=/library/en-us/com/htm/cmi_d2l_89uv.asp[/url]
   Implements UCOMIEnumString

   Public strArray As ArrayList
   Private Pos As Integer = 0

   Public Function [Next](ByVal celt As Integer, ByVal rgelt As String(), ByRef pceltFetched As Integer) As Integer Implements UCOMIEnumString.Next
       Dim retval As Integer = 1
       pceltFetched = 0
       While Not Pos = strArray.Count AndAlso Not pceltFetched = celt
           rgelt(pceltFetched) = strArray(Pos)
           pceltFetched += 1
           Pos += 1
       End While

       If Not pceltFetched.CompareTo(celt) = -1 Then
           retval = 0
       End If

       Return retval

   End Function

   Public Function Skip(ByVal celt As Integer) As Integer Implements UCOMIEnumString.Skip
       Dim retval As Integer = 1
       Pos += celt

       If Not Pos = strArray.Count Then
           retval = 0
       End If

       Return retval
   End Function

   Public Function Reset() As Integer Implements UCOMIEnumString.Reset
       Pos = 0
       Return Pos
   End Function


   Public Sub Clone(ByRef ppenum As UCOMIEnumString) Implements UCOMIEnumString.Clone
       '/// create a Clone of this Class
       ppenum = DirectCast(Me, EnumString)
   End Sub

End Class

#End Region

#Region " AutoComplete Show Options Enums "

Public Enum ShowOptions
   ACO_NONE = 0
   ACO_AUTOSUGGEST = &H1
   ACO_AUTOAPPEND = &H2
   ACO_SEARCH = &H4
   ACO_FILTERPREFIXES = &H8
   ACO_USETAB = &H10
   ACF_UPDOWNKEYDROPSLIST = &H20
   ACO_RTLREADING = &H40
End Enum

#End Region

included as always a sample project...

iautocomplete.zip

[Derek Stone]

Good stuff! :)

[dynamic_sysop]

thanks for the compliment Derek :)