Help, Getting All the ClassNames in a Window

Hi Guys,

Just got this problem right now. I am trying to create a application where in

1. when I click the a button all the active windows in the desktop will be listed in a listbox with their window texts (Done)
2. When I select 1 from them and click another button, all the object classnames in that form will be listed in to another list box (not done)

My problem is that the GetClassName API is not working in VB.NET 2008. I don't know why but I am getting a blank strings. I tried it in VB6 and it works fine.

Can any one help me

Just a thought, have you changed the Longs to integers in the GetClassName declaration ?

Casey.

Use the API Viewer utility (link in my signature) and set its format to VB.NET. Much easier.

Then if your still getting issues post your code.

wierd.. i posted in the wrong window :D

here is the code

vb Code:

Function GetWindowItems(ByVal hwi As Integer, ByVal lst As ListBox) As Integer
        Dim lhndchild As Integer
        Dim strclass As String
        strclass = ""
        lst.Items.Clear()
        lhndchild = GetWindow(hwi, GW_CHILD) 'Ritrive handles of the child windows in the 'control.exe' window
 
        Do
            lhndChild = GetWindow(lhndChild, GW_HWNDNEXT) 'Get text of the fist child window
 
            If lhndChild = 0 Then Exit Do 'IF no more child window to ritrive, then exit.
            Dim MyB As New System.Text.StringBuilder("", 255)
 
            Call GetClassName(lhndchild, strclass, 30) 'get class name of the first child window
            MsgBox(strclass.Length)
            'MsgBox(MyB)
            lst.Items.Add(strclass)
 
        Loop
    End Function

no one wants to help me :D

No its not that, its just hard to work with a program we dont have.

Your code looks ok but can you give more description of where its going instead?

using EnumWindows in .NET is easy, but you must consider that you can't use the AddressOf in the same way as in vb6, so you need to assign a Delegate to handle it.
here's an example i quickly put together for you, it basically grabs all the windows & lists there names & window text ( if they have window text ) in this case in a listview.

Code:

---

Public Class Form1

    '/// modify the 1st arguement of EnumWindows to ByVal lpEnumFunc As winproc
    Private Declare Function EnumWindows Lib "user32.dll" (ByVal lpEnumFunc As winproc, ByVal lParam As Int32) As Int32
    Private Declare Function GetWindow Lib "user32.dll" (ByVal hwnd As IntPtr, ByVal wCmd As Int32) As IntPtr
    Private Declare Function GetClassName Lib "user32.dll" Alias "GetClassNameA" (ByVal hwnd As IntPtr, ByVal lpClassName As System.Text.StringBuilder, ByVal nMaxCount As Int32) As Int32
    Private Declare Function GetWindowText Lib "user32.dll" Alias "GetWindowTextA" (ByVal hwnd As IntPtr, ByVal lpString As System.Text.StringBuilder, ByVal cch As Int32) As Int32
    '/// this will handle the AddressOf issues when using .NET...
    Private Delegate Function winproc(ByVal hwnd As IntPtr, ByVal lparam As Int32) As Int32


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim proc As New winproc(AddressOf ReturnEnumProc)

        EnumWindows(proc, &H0)
    End Sub

    Private Function ReturnEnumProc(ByVal hwnd As IntPtr, ByVal lparam As Int32) As Int32
        Dim sBuilderName As New System.Text.StringBuilder(255)
        Dim sBuilderText As New System.Text.StringBuilder(255)

        GetClassName(hwnd, sBuilderName, 255)
        GetWindowText(hwnd, sBuilderText, 255)

        Dim lvi As New ListViewItem(sBuilderName.ToString)
        lvi.SubItems.Add(sBuilderText.ToString)

        ListView1.Items.Add(lvi)

        Return 1
    End Function
End Class

---

hope it helps :)