Optional parameters cannot have structure types - Visual Basic Discussion Boards

Create a unique Id for each row of table

Seema Bawa1-Feb-12 8:19

1-Feb-12 8:19

I have a table. It desn't have any Id which will be generated automatically.
my table (Table1)has 30 some rows and 3 columns(FirstName, LastName, Occupation).
I want to read each row one by one and wanted to create a unique ID which is of type uniqueIdentifier and fill another table with all these coulmns and newly created ID.

How can I do that

Re: Create a unique Id for each row of table

Simon_Whale1-Feb-12 12:16

Simon_Whale

1-Feb-12 12:16

you haven't said what the database is

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Re: Create a unique Id for each row of table

Eddy Vluggen1-Feb-12 12:30

Eddy Vluggen

1-Feb-12 12:30

Either Paradox 5.0 or DBaseIV format - which would you recommend?

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Re: Create a unique Id for each row of table

Simon_Whale1-Feb-12 21:58

Simon_Whale

1-Feb-12 21:58

Daffodil database[^] Big Grin | :-D

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Re: Create a unique Id for each row of table

RobCroll1-Feb-12 16:14

RobCroll

1-Feb-12 16:14

EDIT: Sorry I misread the question.
Could you iterate through the collection

For i As Integer = 0 To table.count - 1
	Dim selected As Row = table.row(i)
	newTable.add(New Row(i, selected.FirstName, selected.LastName, Occupation))
Next

Alternatively if you are adding to existing table you could use a GUID

For i As Integer = 0 To table.count - 1
	Dim selected As Row = table.row(i)
	newTable.add(New Row(Guid.NewGuid(), forstName, LastName, Occupation))
Next

- Use the database primary key and store in a column those width is 0.
- Some table rows have a tag property you can use to store the entity representing the record
- Some tables are bound directly to a data source, so by querying the selected row, you can access the unique Id.

For a more specific answer, you'll need to detail the scenario. At this stage we don't even know if your talking about a DataGrid, a DataTable or some other matrix type object.

"You get that on the big jobs."

Create a unique Id for Rows

Seema Bawa1-Feb-12 7:58

Seema Bawa

1-Feb-12 7:58

Re: Create a unique Id for Rows

Eddy Vluggen1-Feb-12 8:16

Eddy Vluggen

1-Feb-12 8:16

Why row by row, and not all at once?

SQL

SELECT NEWID()
     , [FirstName]
     , [LastName]
     , [Occupation]
  INTO MyNewTable
  FROM MyExistingTable

--edit;
You would have received more answers if you posted this in the Database[^]-forum.

Bastard Programmer from Hell Suspicious | :suss:

Optional parameters cannot have structure types

Clark Kent1231-Feb-12 5:53

Clark Kent123

1-Feb-12 5:53

That is according to MSDN[^]

I don't understand is... why? I am sure the answer is probably very simple, but for some reason my mind can't come up with the answer. Maybe it's cuz I am so frustrated with this error. Well, who knows.

What do I want to achieve?

Suppose the following...

Public Sub ChangeThePictureBoxBC(Optional newColor as System.Drawing.Color = Drawing.Color.Black)

Me.SomePictureBox.BackColor = newColor

End Sub

This does not seem wrong to me. Can someone please explain A) why the above sub is wrong without re-quoting the unhelpful MSDN document and B) what suggestion/advice can you give me to make an optional parameter that involves color.

Thanks in advance.

Re: Optional parameters cannot have structure types

Eddy Vluggen1-Feb-12 6:34

Eddy Vluggen

1-Feb-12 6:34

Clark Kent123 wrote:
A) why the above sub is wrong

Only nullable types can be used as optional parameters; a struct is a value-type and can't be empty.

Clark Kent123 wrote:
B) what suggestion/advice can you give me to make an optional parameter that involves color.

Overloading[^], instead of optional parameters;

Public Overloads Sub ChangeThePictureBoxBC(newColor as System.Drawing.Color) 
    Me.SomePictureBox.BackColor = newColor
End Sub

Public Overloads Sub ChangeThePictureBoxBC()
    Me.SomePictureBox.BackColor = Drawing.Color.Black
End Sub

Bastard Programmer from Hell Suspicious | :suss:

Re: Optional parameters cannot have structure types

Clark Kent1231-Feb-12 7:16

Clark Kent123

1-Feb-12 7:16

Overloading! Yeah, that's probably the direction that I will go in. Great suggestion! Thumbs Up | :thumbsup:

Re: Optional parameters cannot have structure types

Eddy Vluggen1-Feb-12 7:41

Eddy Vluggen

1-Feb-12 7:41

Thanks

From Variant/double() to Double()

PozzaVecia31-Jan-12 11:54

PozzaVecia

31-Jan-12 11:54

I'm reading a range from VBE code in a spreadsheet.

data  = mySheet.Range(a1:a8).value

but I need to get data as Double() and not as Variant

I need something like:

Dim data() as Double
data  = mySheet.Range(a1:a8).value

this because I will use data as c# arg of Com addins (double[])

Thanks for your time

Re: From Variant/double() to Double()

Eddy Vluggen1-Feb-12 9:47

Eddy Vluggen

1-Feb-12 9:47

TheGermoz wrote:
this because I will use data as c# arg of Com addins (double[])

I haven't scripted that much yet, but wouldn't it be easier to change the params of the Com addins to (object[])?

Put a breakpoint on it, and see if you can cast/convert it to double's.

Bastard Programmer from Hell Suspicious | :suss:

Re: From Variant/double() to Double()

PozzaVecia1-Feb-12 10:28

PozzaVecia

1-Feb-12 10:28

thanks you for your replay. Com addin is shared with other application. so not so easy.
It is surprising that from VBE code in spreadsheet it is not possible to copy an Excel range into an array of double() with one dimension.

Re: From Variant/double() to Double()

Wes Aday1-Feb-12 10:07

Wes Aday

1-Feb-12 10:07

TheGermoz wrote:
data as Double() and not as Variant

Have you tried Array.Copy?

Why is common sense not common?
Never argue with an idiot. They will drag you down to their level where they are an expert.
Sometimes it takes a lot of work to be lazy
Individuality is fine, as long as we do it together - F. Burns

Re: From Variant/double() to Double()

PozzaVecia1-Feb-12 10:30

PozzaVecia

1-Feb-12 10:30

Array.Copy() is not available from VBE but from VBA/C#, so I need to change the COM addin..that is shared with other application...

Convert MS Word doc to PDF

ivo7531-Jan-12 5:58

ivo75

31-Jan-12 5:58

How to Convert MS Word 2003 doc to PDF

Re: Convert MS Word doc to PDF

thatraja31-Jan-12 6:40

thatraja

31-Jan-12 6:40

Go with opensources like ITextSharp[^]. Also check the below one
Convert Doc to PDF with the Help of MS Word and Adobe Acrobat[^]

thatraja

FREE Code Conversion VB6 ASP VB.NET C# ASP.NET C++ JAVA PHP DELPHI | Nobody remains a virgin, Life screws everyone Sigh | :sigh:

Re: Convert MS Word doc to PDF

Abhinav S31-Jan-12 6:41

Abhinav S

31-Jan-12 6:41

You can use a tool like PDFSharp[^] to do this type of conversion.

Using the Save As PDF plugin [^]can help you out as well. It requires an install though.

ITextSharp[^] can be used to create PDF's.

Open office is another utility that you can use - this article describes using it - Converting Microsoft Word Document to PDF format using OpenOffice.org (Portable)[^].

How can I avoid multi-threading?

Rick McLeod30-Jan-12 19:44

Rick McLeod

30-Jan-12 19:44

I am currently in the process of learning the vb.net environment after spending a number of years using VB6.

I took one of my straight forward single threaded apps in VB6 and used the upgrade wizard to convert this app to .net. I've got most of the conversion issues resolved, but I am now getting messages warning about accessing objects from a thread different than the one that created the object. So I'm a bit confused since the original VB6 app - which works fine by the way - had only one thread.

Why am I getting these sorts of messages? I've searched through the code - with my limited exposure to multithreading - and not found anything obvious that I've somehow created a Hydra from a single snake.

My preference would be how to "just make it simple" - a single threaded .net app. All of the references I find to multithreading talk about how to do it. I really - at least at this point - want to know how to avoid it.

I know that soon I will wade in and learn multithreading, but I'd like to do it on my terms.

Any ideas? Pointers to some reference material?

Thanks,

Rick

Re: How can I avoid multi-threading?

Simon_Whale31-Jan-12 1:18

Simon_Whale

31-Jan-12 1:18

simple answer is to remove the

dim myThread as new thread(addressof ThreadCodeSubRoutine)
myThread.Start

and replace it with the call to the ThreadCodeSubRoutine. But .NET introduced thread saftey so you have to invoke a routine to update the controls that are on your form. a bit similar to

Delegate Sub UpdateMyForm(byref SomeValue as string)

 Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
       dim MyThread as new thread(addressof MyThreadCode)
       MyThread.start("HI")
 End Sub

 Private MyThreadCode(byval Message as string)
       dim DelegateVariable as new UpdateMyForm(Addressof WriteToLabel)
       me.Invoke(DelegateVariable, Message)
 End Sub

 Private Sub WriteToLabel(byval Message as String)
       label1.Text = Message
 end sub

But Also have a read of this MSDN Control.Invoke Method (for Threads use)[^]

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Re: How can I avoid multi-threading?

Rick McLeod31-Jan-12 5:34

Rick McLeod

31-Jan-12 5:34

Ah, but here's the rub... there is no command in the code that invokes a new thread. I searched through the entire project looking for "thread" or "addressof" and found nothing. That's what gotten me perplexed - can't seem to find out how or where the second thread (if there is one) gets created.

The messages mentioning threads are related to updating form objects, so should I assume that the "thread safety" is the culprit here? In other words, even for a simple single threaded application, do I need to create a separate thread to handle form updating?

Rick

Re: How can I avoid multi-threading?

Luc Pattyn31-Jan-12 1:58

Luc Pattyn

31-Jan-12 1:58

you may want to read:
- http://perceler.com/articles1.php?art=asyncpool1[^] to find out where the other threads are coming from;
- http://perceler.com/articles1.php?art=crossthreads1[^] to find a way out.

One of these articles is rather C#-oriented, however the concepts are the same in all .NET languages.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.

Re: How can I avoid multi-threading?

Dave Kreskowiak31-Jan-12 2:13

Dave Kreskowiak

31-Jan-12 2:13

You're going to have to show the code that's throwing up the errors. I've never seen a case where the conversion wizard generates threaded code on its own.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: How can I avoid multi-threading?

Bernhard Hiller31-Jan-12 20:55

Bernhard Hiller

31-Jan-12 20:55

There are some possibilities to run into multi-threading without directly intending it.
When you communicate with other applications (e.g. an outproc COM server), events can come from other threads.
If you use the application framework for running only one instance of your application, a second start of the application will send the calling parameters to the running application in a different thread.
Use the Invoke/BeginInvoke function to transfer the call into the main thread.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.