API Newbie

Ok, I've read all over in the FAQ's etc about API's but i dont understand what they do.
Is there a basic turtorial to get one of these running?

This is what i wanted to do:

Make a program in VB, that interacts with a terminal emulated program.
I wanted to be able to just type in a "Order number" hit "go or search" and it does all the functions like i was in the terminal program it self.
I wont be updating records etc, i just want the information out of the info.
Here is a screen shot.

http://www.vbforums.com/

kk anyone?

You can execute a hidden shell and stream the output.

I used to do that with ping, it worked ok. I'll see if I can scrape together an example.

I think this is what sevehalo meant...maybe:

VB Code:

Dim path As String = "C:\Program Files\Java\jdk1.5.0_05\bin"
        Dim p As Process
        p = New Process
        p.StartInfo.CreateNoWindow = True
        p.StartInfo.WorkingDirectory = path
        p.StartInfo.Arguments = "HelloWorld"
        p.StartInfo.FileName = "java.exe"
        p.StartInfo.UseShellExecute = False
        p.StartInfo.RedirectStandardOutput = True
 
        p.Start()
        p.WaitForExit()
        Dim io As String = p.StandardOutput.ReadToEnd()

Note: HelloWorld is a java program - filename HelloWorld.class

Whatever the output that shows up in the console is the string you end up with from the line: Dim io As String = p.StandardOutput.ReadToEnd()

If this isn't what you meant, then just ignore it.

Does anyone have an basic exmample of API used to get text from Note pad and display that text into a text box in the VB application?

Ive been trying to figure this out for days now. I tried the examples above but cant figure it out.

this gets the text from an open notepad(make sure there are some text on the notepad so you can see a result)

VB Code:

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Integer
 
 
    Public Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, ByVal hWnd2 As Integer, ByVal lpsz1 As String, ByVal lpsz2 As String) As Integer
 
    Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
 
    Public Const WM_GETTEXT = &HD
 
    Private Sub proc()
        Dim hwnd As Integer
        Dim hwndEx As Integer
 
        'gets handle of notepad
        hwnd = FindWindow("Notepad", vbNullString)
 
        'gets handle of 'edit' area of notepad
        hwndEx = FindWindowEx(hwnd, vbNullString, "edit", vbNullString)
        Dim len As Integer = 255
        Dim buffer As String    'buffer will contain the text from notepad
        buffer = Space(len)
        
        'sends WM_GETTEXT message to 'edit' area of notepad
        Dim x As Integer = SendMessage(hwndEx, WM_GETTEXT, len, buffer)
        buffer = buffer.Substring(0, x)  
 
    End Sub

when i try that code i get these erros:

http://img403.imageshack.us/img403/2166/error2gn.th.jpg

that code is meant for vb.net. You are obviously using vb 6.0. To fix:

change all integers to 'long' type
On situation with Dim x as integer = 1; change to:
Dim x as integer
x = 1
And instead of using WM_GETTEXT, just substitute the value 13.

vb6 doesn't have .substring, you have to figure out how to do some string manipulation

Quote:

---

Originally Posted by benmartin101

that code is meant for vb.net. You are obviously using vb 6.0. To fix:

change all integers to 'long' type
On situation with Dim x as integer = 1; change to:
Dim x as integer
x = 1
And instead of using WM_GETTEXT, just substitute the value 13.

vb6 doesn't have .substring, you have to figure out how to do some string manipulation

---

I changed all that but i get errors:
Public const 13 = &HD
buffer = Space(len)
x = SendMessage(hwndEx, WM_GETTEXT, len, buffer)

**
Does anyone have a VB 6.0 basic api call to notepad to get the text and put it in a text box in the VB app?

http://img328.imageshack.us/img328/9633/adf2ad.th.jpg

You misunderstood me on the 13 part. I meant, instead of using variablle WM_GETTEXT in one of the parameters, just put value 13.

make buffer = space(len) to buffer = " " make it 255 blank spaces.

Ok i hope i did this right, here is what i have, atleast it builds, but when i hit the button it dosent do anything":

VB Code:

Option Explicit
 
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, ByVal hWnd2 As Integer, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Long
 
    Public Sub proc()
        Dim hwnd As Long
        Dim hwndEx As Long
 
        'gets handle of notepad
        hwnd = FindWindow("Notepad", vbNullString)
 
        'gets handle of 'edit' area of notepad
        hwndEx = FindWindowEx(hwnd, vbNullString, "edit", vbNullString)
        Dim x As Integer
        x = 1
        Dim buffer As String    'buffer will contain the text from notepad
        buffer = "                                                       "
        
        'sends WM_GETTEXT message to 'edit' area of notepad
        Dim x As Integer
        x = SendMessage(hwndEx, 13, buffer)
        buffer = buffer.Substring(0, x)
        Text1.Text = buffer
 
    End Sub

anyone?

I'm not sure if you're even looking at the sample code. Your sendmessage() only has 3 parameters, when the sample code shows 4.

I am looking at it, i dont know what values to pass into there.
That is why i posted in these forums.

I guess a simple API to notepad is turning into a nightmare.

'You cant have public declares or public constants in form code

'You cant dim a var and assign it a value all at once
'len is a reserved word cant dim it as a var (all .NET stuff)
'buffer.Substring(0, x) more .NET
'In hwndEx = FindWindowEx(hwnd, vbNullString, "edit", vbNullString) you are passing the second param as a string, its looking for an Integer
'also placing the 'buffer' in the wrong param of sendmessage


So,

VB Code:

Option Explicit
Private Const WM_GETTEXT          As Long = &HD
Private Const WM_GETTEXTLENGTH    As Long = &HE
 
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, _
                                                                     ByVal lpWindowName As String) As Integer
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, _
                                                                         ByVal hWnd2 As Integer, _
                                                                         ByVal lpsz1 As String, _
                                                                         ByVal lpsz2 As String) As Integer
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, _
                                                                       ByVal wMsg As Integer, _
                                                                       ByVal wParam As Integer, _
                                                                       ByVal lParam As String) As Integer
Private Sub Form_Load()
 
Dim hwnd       As Integer
Dim hwndEx     As Integer
Dim intlen     As Integer
Dim buffer     As String
 
    hwnd = FindWindow("Notepad", vbNullString)
    'gets handle of 'edit' area of notepad
    hwndEx = FindWindowEx(hwnd, 0, "edit", vbNullString)
 
    intlen = SendMessage(hwndEx, WM_GETTEXTLENGTH, 0, vbNullString)
    
    buffer = Space$(intlen)
    
    SendMessage hwndEx, WM_GETTEXT, intlen, ByVal buffer
       
    MsgBox buffer
    
End Sub

Thanks for your help.
Ok i tried running the code, but it only puts blank values into the msgbox, and when i changed the code to put it into the text1 field, it just puts blank spots, and i have text in notepad.

VB Code:

Option Explicit
Private Const WM_GETTEXT          As Long = &HD
Private Const WM_GETTEXTLENGTH    As Long = &HE
 
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, _
                                                                     ByVal lpWindowName As String) As Integer
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, _
                                                                         ByVal hWnd2 As Integer, _
                                                                         ByVal lpsz1 As String, _
                                                                         ByVal lpsz2 As String) As Integer
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, _
                                                                       ByVal wMsg As Integer, _
                                                                       ByVal wParam As Integer, _
                                                                       ByVal lParam As String) As Integer
Private Sub Command1_Click()
 
Dim hwnd       As Integer
Dim hwndEx     As Integer
Dim intlen     As Integer
Dim buffer     As String
 
    hwnd = FindWindow("Notepad", vbNullString)
    'gets handle of 'edit' area of notepad
    hwndEx = FindWindowEx(hwnd, 0, "edit", vbNullString)
 
    intlen = SendMessage(hwndEx, WM_GETTEXTLENGTH, 0, vbNullString)
    
    buffer = Space$(intlen)
    
    SendMessage hwndEx, WM_GETTEXT, intlen, ByVal buffer
       
    Text1.Text = buffer
    
 
End Sub

works for me.

Quote:

---

Originally Posted by Jmacp

works for me.

---

Weird, i can see it copies the text from Notepad, but they are just spaces when they are displayed in my VB app.

Do i need to include an references to anything?

Right now, i typed Hellocheckme on Notepad, I hit the button, and it puts however many spaces HelloCheckme is into the text field.

Beats me then, just tried it again no probs, did you cut and copy the code ?

Yeah, i copy and cut the whole code, and added a textbox and button.

Its weird, it seems to work, but just puts blank spots in there. It does the correct amount of spots, just no text lol.
I tried to copy the blank spots out of the textbox and past them into work, and they are all blank spots. :(

here, i think this might help

VB Code:

'declerations:
Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Declare Function SendMessageByNum& Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long)
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
 
 
Private Sub Command1_Click()
Dim notepad&, notepadedit&, num&, buff$, edittxt&
 
'--find the right windows--
notepad& = FindWindow("Notepad", vbNullString)
notepadedit& = FindWindowEx(notepad&, 0&, "Edit", vbNullString)
'--
'--create a buffer the length of the string that needs to be loaded
num& = SendMessageByNum(notepadedit&, 14, 0, 0&)
buff$ = Space$(num&)
'--
'--actually retrieve the text-
edittxt& = SendMessageByString(notepadedit&, 13, num& + 1, buff$)
 
 
Text1.text = buff$
End Sub

OMG yes that worked, so what did we do different?

i just declared the variables corretly really, but it was easier to write the code over than edit the other one. i added sendmessagebynum and sendmessagebystring, just because i use them to remember my different uses of the SendMessageA function in user32.dll. sendmessage, sendmessagebynum,and sendmessagebystring are all the same call.

Thanks for the help, is there a way now i can get the text from this:

http://www.vbforums.com/

if there is a will. there are several ways to do it though, is the window title caption always the same? does the classname change? i don't have that program so i don't know exactly what the best way to go about it would be. one must study its habbits

Yes, the name of the program stays that same, with those values.

I checked it a few times with Spy++

here is my code, i press the button but it dosent get anything:

Here is whats in my button click

VB Code:

Dim notepad&, notepadedit&, num&, buff$, edittxt&
 
'--find the right windows--
notepad& = FindWindow("PCSWS:Main:00400000", vbNullString)
notepadedit& = FindWindowEx(notepad&, 0&, "PCSWS:Pres:00400000", vbNullString)
'--
'--create a buffer the length of the string that needs to be loaded
num& = SendMessageByNum(notepadedit&, 14, 0, 0&)
buff$ = Space$(num&)
'--actually retrieve the text-
edittxt& = SendMessageByString(notepadedit&, 13, num& + 1, buff$)
Text1.Text = buff$

sendmessage in this context is for edit controls, and that my friend isn't an edit control...its a pcws whatever it is, i'm not a very good teacher, i'd have to have the program, or else i'll be posting a code i think will work, instead of pressing run to find out.

Oh i thought this code would work in the same way the one with notepad did.
I figure i would just find the program, then copy all the text, and display in the box.

do you have aim?

ANyone?