Component Handles
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From: Dee Earley on 8 Oct 2009 08:19 On 06/10/2009 17:46, xytsrm wrote: > "Dee Earley" wrote: >> The text box contents are not the "caption" which si why FindWindow* >> won't see it. >> You need to enumerate them all (EnumWindows()) and check for one that >> looks like the one you want, possibly extracting and checking the text >> manually. > > Actually the property in the textbox is not "caption", it's "name", but as > some have suggested the name is not exposed and needs to be enumerated, or > perhaps can be found through Winspector. Sorry, I used "Caption" as that is what Spy++ labeled it as, presumably for statics and plain windows where that text is the caption. The point is that the "name" for VB created textboxes is blank and is not the contents of the textbox. -- Dee Earley (dee.earley(a)icode.co.uk) i-Catcher Development Team iCode Systems
From: Dee Earley on 8 Oct 2009 08:52 On 08/10/2009 08:21, Eduardo wrote: > Nobody escribi�: >> "Eduardo" <mm(a)mm.com> wrote in message news:hajk12$6d9$1(a)aioe.org... >>> I don't know if with EnumChildWindows they also appear ordered this way. >> >> Yes they are. Quote from the remarks section: "A child window that is >> moved or repositioned in the Z order during the enumeration process >> will be properly enumerated. The function does not enumerate a child >> window that is destroyed before being enumerated or that is created >> during the enumeration process." > > OK. I like the GetWindow method because it's easier. > > And about the problems... they don't specify how they could happen, but > I suspect that for looking for form's controls handles in a fast loop > when you are not removing or adding controls or changing the Zorder, it > should be fine; and also for finding a textbox (it's a guess). Yes, IF they don't change, move, shutdown, get reused, get rubbed up against by the nearest cat, shot, hung, drawn or quartered. It's much easier to use a reliable method rather than one that is documented as causing problems... -- Dee Earley (dee.earley(a)icode.co.uk) i-Catcher Development Team iCode Systems
From: Eduardo on 8 Oct 2009 09:34 It wasn't hard to fix the "problem": Option Explicit Private Declare Function GetWindow Lib "USER32" (ByVal hwnd _ As Long, ByVal wFlag As Long) As Long Private Declare Function GetWindowText Lib "USER32" Alias _ "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As _ String, ByVal cch As Long) As Long Private Declare Function FindWindow Lib "USER32" Alias _ "FindWindowA" (ByVal lpClassName As String, ByVal _ lpWindowName As String) As Long Private Declare Function GetClassName Lib "USER32" Alias _ "GetClassNameA" (ByVal hwnd As Long, ByVal _ lpClassName As String, ByVal nMaxCount As Long) As Long Private Const GW_HWNDNEXT = 2& Private Const GW_CHILD = 5& Private Function GetFirstTextBoxHandle(nFormCaption As String, _ Optional nTextboxText As String) As Long Dim iHwnd As Long Dim iSize As Long Dim iClass As String Dim iText As String Dim iCount As Long iHwnd = FindWindow(vbNullString, nFormCaption) If iHwnd Then iHwnd = GetWindow(iHwnd, GW_CHILD) Do While iHwnd iClass = Space(64) iSize = GetClassName(iHwnd, iClass, Len(iClass)) If iSize > 0 Then iClass = Left(iClass, iSize) If Left(iClass, 7) = "Thunder" Then If Right(iClass, 7) = "TextBox" Then If nTextboxText <> "" Then iText = Space(100) GetWindowText iHwnd, iText, 100& iText = Left(iText, InStr(iText, _ Chr(0)) - 1) If iText = nTextboxText Then GetFirstTextBoxHandle = iHwnd Exit Function End If Else GetFirstTextBoxHandle = iHwnd Exit Function End If End If End If iCount = iCount + 1 If iCount > 500 Then Exit Function End If iHwnd = GetWindow(iHwnd, GW_HWNDNEXT) Loop End If End Function Private Sub Command1_Click() MsgBox GetFirstTextBoxHandle("OtherForm1", "Text1") End Sub
From: Eduardo on 8 Oct 2009 09:37 Sorry, again: Option Explicit Private Declare Function GetWindow Lib "USER32" (ByVal hwnd _ As Long, ByVal wFlag As Long) As Long Private Declare Function GetWindowText Lib "USER32" Alias _ "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As _ String, ByVal cch As Long) As Long Private Declare Function FindWindow Lib "USER32" Alias _ "FindWindowA" (ByVal lpClassName As String, ByVal _ lpWindowName As String) As Long Private Declare Function GetClassName Lib "USER32" Alias _ "GetClassNameA" (ByVal hwnd As Long, ByVal _ lpClassName As String, ByVal nMaxCount As Long) As Long Private Const GW_HWNDNEXT = 2& Private Const GW_CHILD = 5& Private Function GetFirstTextBoxHandle(nFormCaption As String, _ Optional nTextboxText As String) As Long Dim iHwnd As Long Dim iSize As Long Dim iClass As String Dim iText As String Dim iCount As Long iHwnd = FindWindow(vbNullString, nFormCaption) If iHwnd Then iHwnd = GetWindow(iHwnd, GW_CHILD) Do While iHwnd iClass = Space(64) iSize = GetClassName(iHwnd, iClass, Len(iClass)) If iSize > 0 Then iClass = Left(iClass, iSize) If Left(iClass, 7) = "Thunder" Then If Right(iClass, 7) = "TextBox" Then If nTextboxText <> "" Then iText = Space(100) GetWindowText iHwnd, iText, 100& iText = Left(iText, InStr(iText, _ Chr(0)) - 1) If iText = nTextboxText Then GetFirstTextBoxHandle = iHwnd Exit Function End If Else GetFirstTextBoxHandle = iHwnd Exit Function End If End If End If End If iHwnd = GetWindow(iHwnd, GW_HWNDNEXT) iCount = iCount + 1 If iCount > 500 Then Exit Function Loop End If End Function Private Sub Command1_Click() MsgBox GetFirstTextBoxHandle("OtherForm1", "Text1") End Sub
From: mayayana on 8 Oct 2009 10:20
I wonder about the difference, too. MS doesn't provide any technical explanation for their statement. But for what it's worth, I find the EnumChildWindows method fairly simple. It just requires writing a small callback function and using a bas-global variable. Also, there seems to be another important difference: According to the docs it seems that GetWindow only goes down one level, while EnumChildWindows seems to return the entire hierarchy before quitting. That's not always relevant, but in many cases a window that's expected to be 1 level down might actually be 2 or 3 levels down, nested in intermediary windows. The following is a snippet that I wrote for finding an IE browser window in a given folder window hierarchy. The full enum was needed in that case because different Windows versions have different folder window structures. I edited this code slightly to produce a sample function that returns an hWnd based on part of any window class name: ' GetWindowByClass function is called to set the enum going. ' The EnumChildProc takes it from there. It checks ' the class name of each window. Returning 0 ' stops the enum. So this example of EnumChildProc ' runs until either all child windows have been ' processed or a match has been found. That all ' happens before the last line of GetWindowByClass. ' By that point the variable HCur is either 0 or the ' hWnd of a window with matching classname. Private Function GetWindowByClass(ByVal TophWnd As Long, sClass As String) As Long Dim LRet As Long HCur = 0 'module-level variable. GetWindowByClass = 0 sClassName = sClass 'module-level variable. LRet = EnumChildWindows(TophWnd, AddressOf EnumChildProc, 0) GetWindowByClass = HCur '-- either 0 or hWnd. End Function Public Function EnumChildProc(ByVal hWnd As Long, lParam As Long) As Long Dim s2 As String s2 = GetWinClass(hWnd) If InStr(1, s2, sClassName, 1) > 0 Then HCur = hWnd EnumChildProc = 0 Else EnumChildProc = 1 End If End Function Public Function GetWinClass(ByVal H1 As Long) As String Dim sBuf As String Dim LRet As Long On Error Resume Next GetWinClass = "" sBuf = String$(256, 0) LRet = GetClassName(H1, sBuf, Len(sBuf)) If (LRet > 0) Then GetWinClass = Left$(sBuf, LRet) End Function |