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Calling a form within a DLL

Posted on 2003-12-03
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Last Modified: 2010-05-01
This is a follow up of question:

http://www.experts-exchange.com/Programming/Programming_Languages/Visual_Basic/Q_20814217.html

I need to get vector information from a database, transform it into an image, save the image to a file (with a random filename), pass some database information as well as the filename of the image file to a web page for display. (I will have another routine clean up the files so that there isn't a disk space problem)

I currently have two VB projects that do the following:
1) A DLL that will return the needed data from a database. (I can call this DLL from a web page and display the data)
2) A project that has form that can transform the data into an image and save it to a file. (If I hard code the data I can run the project and create an image file)

I need to know:
A) How to pass the database information to the form (the data needed is a char(20) and an variable size array of char(60))
B) How to pass the filename of the created file back to the DLL and then back to the web page that will display the image

I'm not sure if I need to create an Executable from the project (number 2) and run it from the DLL. Or if I need to include the form in the DLL and call it internally.

Urgent help is needed. (I will only be in the office till 11:00 am EST and not back until Monday 12/8 and I'd like to have this working before I leave)
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Question by:resedlar
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Expert Comment

by:EDDYKT
ID: 9866973
A. just pass as recordset
B. You are not passed as file name, open the file and read the content as pass the content as string
On the other end, just load the string to picturebox
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Accepted Solution

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AzraSound earned 500 total points
ID: 9867274
In the dll that contains the form, you still need a class which should contain an instance of that form.  E.g.,


Option Explicit

Private m_frmPicture As NameOfFormInMyDLL



Public Function TransferToFile(ByVal DatabaseData As Variant) As String

    'manipulate data to create picture and save to file

    'return file name
    TransferToFile = strFileNameCreated

End Sub



Private Sub Class_Initialize()
    Set m_frmPicture = New NameOfFormInMyDLL
    Load m_frmPicture
End Sub

Private Sub Class_Terminate()
    Unload m_frmPicture
    Set m_frmPicture = Nothing
End Sub




Then, from your asp page:


<%
Dim objDrawPicture, strFile

Set objDrawPicture = Server.CreateObject("MyDLL.DrawPicture")
strFile = objDrawPicture.TransferToFile(vMyDBData)
%>

<img src="<%=strFile%>">
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Author Comment

by:resedlar
ID: 9867513
Thanks AzraSound,

I have made the changes to the DLL that you listed. Recreated the DLL and reinstalled it in COM+ I am now getting an error in my ASP page that reads:

Server object, ASP 0177 (0x80010007)
The callee (server [not server application]) is not available and disappeared; all connections are invalid. The call may have executed.
/RealEstate/sketch.asp, line 49

Line 49 is the "set objDrawpicture=Server.CreateObject("MyDLL.DrawPicture") line.

I need to go to training for the rest of the week so, I'll not be able to debug again till Monday.
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Author Comment

by:resedlar
ID: 9867558
OK,

Now that I have actually closed Component services, I am getting an error on the "strFile = objDrawPicture.TransferToFile(vMyDBData)" line:

Automation error

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LVL 28

Expert Comment

by:AzraSound
ID: 9867585
Hard to say without some debugging.  I assume vMyDBData is a variable actually containing the data you have pulled from your database?
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Author Comment

by:resedlar
ID: 9897147
Typos, Typos, Typos. Now that I have fixed them everything is working great.

Thanks Azra

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