WM_NOTIFY Reports incorrect values - Visual Basic Discussion Boards

Hi,

I am using a treeview and I saw a neat way of adding your own type of nodes using a class derived from TreeNode. My class is the same as a tree node but it has a key property I can use to index into collections of other stuff

class TreeNodeCommand
Inherits TreeNode

Public Key as string

End Class

In order to make my code slick I then wrote two conversion functions, so that any nodes returned from treeview are converted to TreeNodeCommand...

Private Function CurrentNode() As TreeNodeCommand
Return ToTreeNodeCommand(tvwCommands.SelectedNode)
End Function

Private Function RootNode() As TreeNodeCommand
Return ToTreeNodeCommand(tvwCommands.Nodes.Item(0))
End Function

' Convert tree node item to tree node command item
Private Function ToTreeNodeCommand(ByRef prItem As TreeNode) As TreeNodeCommand
Return CType(prItem, TreeNodeCommand)
End Function

OK, thats the background. I have a treeview that refers to TreeNodeCommands rather than TreeNodes.

I have drag and drop support on this treeview, but I dont want the user to be able to drop a particular thing on the Root node. So in my dragover code I select the node in the treeview under the mouse and using my CurrentNode and RootNode properties I check to see if they are the same node....

If Not CurrentNode Is RootNode Then
e.Effect = DragDropEffects.Copy
End If

...but guess what. Every single time the IF statement executes, I get another node added to the tree, which is effectively a CLONE of the root node.

If I do this, which is perfectly acceptable, but not as slick to read then all is well...

If Not tvwCommands.SelectedNode Is tvwCommands.Nodes(0) Then
e.Effect = DragDropEffects.Copy
End If

You will have had to see this to believe it. No where does any single line of code get executed that does a ...Nodes.Add. Yet, new nodes do appear.

I can work around this, but I would be really interested to see if for some reason you think the Clone method of the root node is being invoked by the type conversion, or by some other means. I think that's what it is. The interesting thing is I override the Clone method in my derived class and it doesn't get called at any time.

So, I am lost in la la land with this one people. Any thoughts or similar experiences would be appreciated. Perhaps I am missing something due to my lack of .NET experience.

Apologies for the lengthy post.

Nursey

It does seem that the root node is being duplicated by the tree. Here is another case...

' This function reads nodes and adds things to another collection
NodesToCommands(DirectCast(tvwCommands.Nodes(0), TreeNode), _
CommandList.SingletonObject.RootCommandTree)
...

The first parameter tvwCommands.Nodes(0) normally returns TreeNode. Please remember, and forgive my repetition, but in my case it returns a TreeNodeCommand object.

If I had the DirectCast around this parameter all is well. If I do not then the tree from the root node down is duplicated and added back to the tree!

Each time I can find work arounds to this stuff, but why the hell is it happening?

Nursey

Try this.

To access the RootNode tvwCommands.TopNode
Smile | :)

Free your mind...

Hi Guille,

Yeh but I would still cast TopNode to a TreeNodeCommand see? The problem seems to be casting the node causes the tree to duplicate itself, get me?

Nursey

can someone pls tell me how do i do this when using a rtf???
[code]
Dim strHeading as string
dim strLabel as string
strheading = "====================================="
strlabel = "S.No Name Contents DateCreated"
[/code]
how do i put the str heading in one line of the rtf?
how do i move to the newline?
how do i put the strLabel in the new line?
how do i bring the cursor to the next new line?
tks a lot....
really really appreciate your help...

"Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you."1Thess. 5:16-18

When I need to do this, I open wordpad (not word) and i type in some text, do some formatting and examine the structure of the generated rtf file Smile | :)

greetz

*Niels Penneman*

Software/Dev Site
Personal Site

I have a question that may or may not be difficult to answer... I've never done anything like this before.

Could anyone provide me with information about how I could use visual basic 6 (not .net) to convert a bitmap image to a 2D array of pixels? I've found a reference page on the format of a BMP file, but it's not as detailed as I would hope... and when I try to use file input from the BMP file, I just come up with mostly null strings instead of usable bytes.

Im new to vb.net and Im trying to move mi apliccations to the new language...and i have the following problem.

Im trying to intercept the ListView messages because i want a LV footer to autoresize when a column resize.
I create a Class inherit a LV and override the WndProc sub. But when i try to intercept the WM_NOTIFY message, the asociated code seems incorrect.

Here is my code (the class):

-----------------------------------------------------------------------------
Public Class MyListView
Inherits System.Windows.Forms.ListView

Structure NMHDR
Dim hwndFrom As Long ' Window handle of control sending message
Dim idFrom As Long ' Identifier of control sending message
Dim code As Long ' Specifies the notification code
End Structure

Structure NMHEADER
Dim hdr As NMHDR
Dim iItem As Long
Dim iButton As Long
Dim lPtrHDItem As Long ' HDITEM FAR* pItem
End Structure

Public Const WM_NOTIFY = &H4E
Public Const WM_PAINT = &HF
Public Const WM_USER = &H400
Public Const WM_REFLECT = WM_USER + &H1C00
Const HDN_FIRST As Long = -300&
Const HDN_LAST As Long = -399&
Const HDN_GETDISPINFO As Long = (HDN_FIRST - 9)
Const HDN_BEGINDRAG As Long = (HDN_FIRST - 10)
Const HDN_ENDDRAG As Long = (HDN_FIRST - 11)
Const HDN_ITEMCLICK As Long = (HDN_FIRST - 2)
Const HDN_ITEMDBLCLICK As Long = (HDN_FIRST - 3)
Const HDN_DIVIDERDBLCLICK As Long = (HDN_FIRST - 5)
Const HDN_ITEMCHANGING As Long = (HDN_FIRST - 0)
Const HDN_ITEMCHANGED As Long = (HDN_FIRST - 1)
Const HDN_BEGINTRACK As Long = (HDN_FIRST - 6)
Const HDN_ENDTRACK As Long = (HDN_FIRST - 7)
Const HDN_TRACK As Long = (HDN_FIRST - 8)
Const NM_FIRST As Long = -0& ' (0U- 0U)
Const NM_CUSTOMDRAW As Long = (NM_FIRST - 12)
Const NM_RCLICK As Long = (NM_FIRST - 5)
Const NM_RELEASEDCAPTURE As Long = (NM_FIRST - 16)
Const NM_CLICK As Long = NM_FIRST - 2
Const LVN_FIRST As Long = 100
Const LVN_COLUMNCLICK As Long = LVN_FIRST - 8

Protected Overrides Sub WndProc(ByRef m As Message)
Dim nmh As NMHDR

Select Case m.Msg

Case WM_NOTIFY
nmh = CType(m.GetLParam(nmh.GetType), NMHDR)
If nmh.code = HDN_BEGINTRACK Then
MsgBox("track")
End If

End Select

MyBase.WndProc(m)

End Sub

End Class
'-----------------------------------------------------------------------------

The WM_NOTIFY is detected OK. But I cant get the HDN_BEGINTRACK code. Instead, I get some stranges values
like 5334658619277312 or 5334486820585472

Please HELP!

Thanks in advance.

First of all, in VB.NET long becomes integer, integer becomes short, ...

This may not solve your problem, but will help you with this and future translations Smile | :)

I suggest you read the translation guidelines @ MSDN

greetz Wink | ;-)

*Niels Penneman*

Software/Dev Site
Personal Site

Thanks a lot Niels!!

Your sugestion was good, it help me a bit...
Now the values looks more "real"....but aparently
appears increased in 20 (i.e.: -326 instead -306)
But now I'm closer to the solution!
Any idea why this happenns?

Values are NOT incorrect... look what I found Smile | :)

Hdn_begintrackw: INTEGER is -326
			-- Notifies a header control's parent window that the user has
			-- begun dragging a divider in the control (that is, the user
			-- has pressed the left mouse button while the mouse cursor is
			-- on a divider in the header control). This notification
			-- message is sent in the form of a WM_NOTIFY message.
			--
			-- Declared in Windows as HDN_BEGINTRACK

I found it here Wink | ;-)

greetz

*Niels Penneman*

Software/Dev Site
Personal Site

Correct translation to VB.NET is here:

Structure NMHDR
    Dim hwndFrom As IntPtr ' Window handle of control sending message
    Dim idFrom As Integer ' Identifier of control sending message
    Dim code As Integer ' Specifies the notification code
End Structure

Structure NMHEADER
    Dim hdr As NMHDR
    Dim iItem As Integer
    Dim iButton As Integer
    Dim lPtrHDItem As IntPtr ' HDITEM FAR* pItem
End Structure

greetz

*Niels Penneman*

Software/Dev Site
Personal Site

Good afternoon!

I want to ask for a VB.Net code for copying files from its source to its destination path.

Thanks in advance!

len_ems

System.IO.File.Copy(source, destination)

How do I get a list of active machines in a network using vb.net?

We need a little more info than this...

Define "active"?
Is it a machine that is connected to the network and turned on, but not doing anything?
Or is it a machine that is "actively" communicating and then not "active" when it is not communicating?
Is it a member of an Active Directory or Novell Directory?

What kind of information are you looking to gather from these "active" machines?

RageInTheMachine9532

Active machines according to me are those of the 2nd type. It would be good if u could get the machines in the active directory also.

Then you really can't do that. You would have to write an app that can capture all the packets that come by the machine it is running on. This would only work on Ethernet segments that are running on hubs. Switches will prevent you from seeing all the packets, which is what most corporate networks are going to be built with.

RageInTheMachine9532

hi...
i want to print something in a formatted manner.. but the thing is that its not from a database. its from collected information withing the program..
basically its read from a lot of files and printed in a orderly manner.. i have all the infor with me.. i just need to print it in the following manner.
the printed matter should look like the post below
can anyone pls help on how can i print in this manner???
actually i need to know how do i put it in some control in sucha way tat the thing will look like a report..
prnting will be easy once i can make it look like the post below...
my prob is how do i arrange it and what control should i use to arrange it in the below manner?? so that later i can just proint out of that control...
tks a lot...really appreciate your help...

"Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you."1Thess. 5:16-18

==========================================================================
S.No | File Name |               File Contents               |Date Created|
1    |test 1     |This is a test ... this is a test..        | 12/12/03   |
     |           |continuing the test..this is a test        |            |
     |           |test.this is the the test that is          |            |
     |           |continued.end of test 1.                   |            |
2    |  test 2   |Start test 2.. test 2 initiating count-    | 13/12/03   |
     |           |down to the start of test 2. ABORT!!!!NOW!!|            |
3    | test 3    |no one likes test 3. KILLED test 3         | 14/12/03   |
4    | test 4    |Anouncing the arrival of test 4!! test 4   |            |
     |           |is here.... initiating startup............ |            |
     |           |couting down for test 4.Crew dead!         |            |
5    | test 5    |Thats all folks!                           |            |
===========================================================================

"Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you."1Thess. 5:16-18

i was wondering...if i put all the info i need into a listview...(which will solve my formatting problem) can i directly proint the contents of the list view to a printer in a aWYSIWYG manner?? Confused | :confused:

"Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you."1Thess. 5:16-18

Hi,hello.I want to create a command button that used to
convert microsoft access file to Excel file.What is the code in vb6 for the command button.

Hi, i have create a program using VB6.The purpose of this program are for sales department person key in the data and then review by manager.Now, my problem is manager want me to create a command button to export the data from microsoft access to excel.What is the command button code and the step? Another Question,this program must set up in the office and all the staff can see and use this program at their own PC's!Thank for ur help!

I'm having all kinds of fun trying to iron out this problem, and im SURE there's an easy solution out there...

I need to use COM interop between unmanaged C++ and VB .NET to have my C++ client catch and respond to events raised in VB .NET. More specifically, I've got a VB .NET custom user ActiveX control with a valid COM interface that I've imported and used in my C++ client. I can make function calls from the COM client to the .NET server, but I cannot seem to handle events from the control.

I'm certainly no expert on COM interop, but I've browsed around and read bits of literature here and there on how to do this to no avail. The control doesn't seem to have any connection points to which I can connect to (which might be the problem), but trying to use ATL SINK_ENTRY with IDispEventImpl hasn't worked, nor has an MFC DECLARE_EVENTSINK_MAP with ON_EVENTs. I'm at a total loss and any help would be greatly appreciated.

P.S. if none of this works, would it be feasible to pass VB a C++ function pointer via its COM interface and then have VB "call" the C++ function using this pointer? They're in the same address space so it should work, but can VB call a function given only an address as a long?

Any suggestions on using a timer to check for a backup log's existence at a certain time every day? Is there some other function I should be using instead of Timer? Newbie needs help. Thanks!

Confused | :confused:

Stacy

At a certain time every day? Doesn't sound like a job for a Timer. Sounds more like using the Scheduled Task control panel. Then your app wouldn't have to bother with the time or a countdown timer.

RageInTheMachine9532