Re: EM_CHARFROMPOS always return -1

#1

Hi Mike,

when uprade this to vb.net, VarPtr is not support but the Help file
provide no alternative to replace. Is there any safe handler to
replace VarPtr?
'UPGRADE_ISSUE: VarPtr function is not supported. Click for more:
'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?
keyword="367764E5-F3F8-4E43-AC3E-7FE0B5E074E2"'
SendMessageTimeout HwndOver, WM_GETTEXT, 255,
VarPtr(WindowTextArray(0)), 0, 1000, 0

Alan

On Apr 18, 3:43 am, "MikeD" <nob... (AT) nowhere (DOT) edu> wrote:

Quote:

ala... (AT) gmail (DOT) com> wrote in message

news:1176826301.501011.121310 (AT) q75g2000hsh (DOT) googlegroups.com...

Hi Mike,

You are really VB WINAPI expert, adding byval does help. However, I
get this declaration from API viewer, it seems that the declaration
from API viewer may not be correct. Oh, I realize that lParam can be
pointer for POINT structure.

No, the declaration in the viewer is correct, it's just "generic". What you
pass for SendMessage's LParam can vary, even the data type. It might be a
String, or a Long, or a structure (not just a POINT structure). That's why
the declaration in the API Viewer has lParam As Any. It's more versatile
this way, but also more error-prone and even somewhat dangerous (not too
difficult to cause the app to crash if you don't pass lParam correctly for
the message you're sending).

What many people do is declare type-safe versions of SendMessage. For
example

Public Declare Function SendMessageByString Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, ByVal lParam As String) As Long

Public Declare Function SendMessageByLong Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, ByVal lParam As Long) As Long

Public Declare Function SendMessageByPOINTAPI Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, lParam As POINTAPI) As Long

As you can see, this takes care of the ByVal keyword (to include or not
include it) in the declaration. Since you didn't include the declaration in
your original post, I couldn't be sure if this was the problem, or if it
could be something, anything, else. You should always include API
declarations when posting your code for this reason and others.

Also, your code might have worked without the ByVal keyword IF you had
assigned the return value of MAKELPARAM to a variable and used that variable
in your call to SendMessage. Not sure about that, but it's probably a better
way to go anyway.

I am author of a pop shareware, to thank you, I can send you a free
license. You can send me email atalanwo[at]gmail[dot]com.

Appreciate the gesture, but that's quite alright.

--
Mike
Microsoft Visual Basic MVP

#2

Mike,

OK, I got it, VarPtr can be repaced by
System.Runtime.InteropServices.Marshal.UnsafeAddrO fPinnedArrayElement

SendMessageTimeout(HwndOver, WM_GETTEXT, 255,
System.Runtime.InteropServices.Marshal.UnsafeAddrO fPinnedArrayElement(WindowTextArray,
0), 0, 1000, 0)

However, this won't work:
r = SendMessage(HwndOver, EM_CHARFROMPOS, 0, MAKELPARAM(pt.X,
pt.Y))

You asked me to add ByVal to MAKELPARAM(pt.X, pt.Y) but it won't work
in vb.net 2.0.

BTW, I found that vb.net 2.0 support GetCharIndexFromPosition:
Me.Text2.GetLineFromCharIndex(Me.Text2.GetCharInde xFromPosition(eventArgs.Location))
However, my goal is to get char index from position of other window /
outside my application. It seem that I have to still use Win32 API.

Do other experts have advice?

FYI, my API declaration:

Public Declare Function SendMessage Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal
wParam As Integer, ByVal lParam As Integer) As Integer

Public Declare Function GetClassName Lib "user32" Alias
"GetClassNameA"(ByVal hwnd As Integer, ByVal lpClassName As String,
ByVal nMaxCount As Integer) As Integer

'UPGRADE_WARNING: Structure POINTAPI may require marshalling
attributes to be passed as an argument in this Declare statement.
Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?
keyword="C429C3A5-5D47-4CD9-8F51-74A1616405DC"'
Public Declare Function ScreenToClient Lib "user32" (ByVal hwnd As
Integer, ByRef lpPoint As POINTAPI) As Integer

'UPGRADE_ISSUE: Declaring a parameter 'As Any' is not supported.
Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?
keyword="FAE78A8D-8978-4FD4-8208-5B7324A8F795"'
'UPGRADE_ISSUE: Declaring a parameter 'As Any' is not supported.
Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?
keyword="FAE78A8D-8978-4FD4-8208-5B7324A8F795"'
Public Declare Sub CopyMemory Lib "kernel32" Alias
"RtlMoveMemory" (ByRef Destination As Object, ByRef Source As Object,
ByVal Length As Integer)

Public Function MAKELPARAM(ByRef wLow As Integer, ByRef wHigh As
Integer) As IntPtr

'Combines two integers into a long
MAKELPARAM = MAKELONG(wLow, wHigh)

End Function

Public Function MAKELONG(ByRef wLow As Integer, ByRef wHigh As
Integer) As Integer

MAKELONG = LoWord(wLow) Or (&H10000 * LoWord(wHigh))

End Function

Public Function LoWord(ByRef dwValue As Integer) As Short

CopyMemory(LoWord, dwValue, 2)

End Function

On Jun 3, 11:52 am, Alan <ala... (AT) gmail (DOT) com> wrote:

Quote:

Hi Mike,

when uprade this to vb.net, VarPtr is not support but the Help file
provide no alternative to replace. Is there any safe handler to
replace VarPtr?
'UPGRADE_ISSUE: VarPtr function is not supported. Click for more:
'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?
keyword="367764E5-F3F8-4E43-AC3E-7FE0B5E074E2"'
SendMessageTimeout HwndOver, WM_GETTEXT, 255,
VarPtr(WindowTextArray(0)), 0, 1000, 0

Alan

On Apr 18, 3:43 am, "MikeD" <nob... (AT) nowhere (DOT) edu> wrote:

ala... (AT) gmail (DOT) com> wrote in message

news:1176826301.501011.121310 (AT) q75g2000hsh (DOT) googlegroups.com...

Hi Mike,

You are really VB WINAPI expert, adding byval does help. However, I
get this declaration from API viewer, it seems that the declaration
from API viewer may not be correct. Oh, I realize that lParam can be
pointer for POINT structure.

No, the declaration in the viewer is correct, it's just "generic". What you
pass for SendMessage's LParam can vary, even the data type. It might be a
String, or a Long, or a structure (not just a POINT structure). That's why
the declaration in the API Viewer has lParam As Any. It's more versatile
this way, but also more error-prone and even somewhat dangerous (not too
difficult to cause the app to crash if you don't pass lParam correctly for
the message you're sending).

What many people do is declare type-safe versions of SendMessage. For
example

Public Declare Function SendMessageByString Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, ByVal lParam As String) As Long

Public Declare Function SendMessageByLong Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, ByVal lParam As Long) As Long

Public Declare Function SendMessageByPOINTAPI Lib "user32" Alias
"SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam
As Long, lParam As POINTAPI) As Long

As you can see, this takes care of the ByVal keyword (to include or not
include it) in the declaration. Since you didn't include the declaration in
your original post, I couldn't be sure if this was the problem, or if it
could be something, anything, else. You should always include API
declarations when posting your code for this reason and others.

Also, your code might have worked without the ByVal keyword IF you had
assigned the return value of MAKELPARAM to a variable and used that variable
in your call to SendMessage. Not sure about that, but it's probably a better
way to go anyway.

I am author of a pop shareware, to thank you, I can send you a free
license. You can send me email atalanwo[at]gmail[dot]com.

Appreciate the gesture, but that's quite alright.

--
Mike
Microsoft Visual Basic MVP- Hide quoted text -

- Show quoted text -

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Re: EM_CHARFROMPOS always return -1

Dotnet Framework (Interop) microsoft.public.dotnet.framework.interop

Re: EM_CHARFROMPOS always return -1 - 06-02-2007 , 11:52 PM

Re: EM_CHARFROMPOS always return -1 - 06-03-2007 , 06:59 AM