Using an array inside of a structure in Visual Basic

Question

I'm trying to create a structure and inside it put an array of "Genres". 

This is my structure declaration:

Structure BookData 
       
Dim strGenres() As String      
Dim strTitle, strAuthor1, strAuthor2, strAuthor3, strPublisher As String        
Dim intBookID, intYearPublished, intNumberOfCopies As Integer        
Dim sngBuyingPrice, sngSellingPrice As Single    

End Structure

And this is where I am trying to call the structure

Public Sub btnSaveDetails_Click()        
Dim LocalBookData As BookData        
Dim LocalBookData.strGenres(5)       
 
LocalBookData.strGenres(0) = "Hello"

End Sub

But I keep getting an error with the .strGenres(5). VB is telling me "End of statement expected"

I don't know where I'm going wrong! I'm basing this off code given to us in the examples and I'm following it perfectly so I don't know what the issue is.

Thanks

Answer 1

Mike

This forum is not for vintage VB try this link to see what to do

http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/6a0719fe-14af-47f7-9f51-a8ea2b9c8d6b

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Success
Cor

Answer 2

What exactly is vintage VB? I'm using visual studio 2010?

Answer 3

I'm trying to create a structure and inside it put an array of "Genres". 

This is my structure declaration:

Structure BookData 
       
Dim strGenres() As String      
Dim strTitle, strAuthor1, strAuthor2, strAuthor3, strPublisher As String        
Dim intBookID, intYearPublished, intNumberOfCopies As Integer        
Dim sngBuyingPrice, sngSellingPrice As Single    

End Structure

And this is where I am trying to call the structure

Public Sub btnSaveDetails_Click()        
Dim LocalBookData As BookData        
Dim LocalBookData.strGenres(5)       
 
LocalBookData.strGenres(0) = "Hello"

End Sub

But I keep getting an error with the .strGenres(5). VB is telling me "End of statement expected"

I don't know where I'm going wrong! I'm basing this off code given to us in the examples and I'm following it perfectly so I don't know what the issue is.

Thanks

Answer 4

What exactly is vintage VB? I'm using visual studio 2010?

In modern VB  your way for a button click

Public Sub btnSaveDetails_Click()        
Dim LocalBookData As BookData        
Dim LocalBookData.strGenres(5)       
 
LocalBookData.strGenres(0) = "Hello"

End Sub

does not exist, it should be at least

    Public Sub btnSaveDetails_Click(sender As Object, e As EventArgs)
        Dim LocalBookData As BookData
        Dim LocalBookData.strGenres(5)       
        LocalBookData.strGenres(0) = "Hello"
    End Sub

But normally is also the handler added to the method

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Success
Cor

Answer 5

It is the second, I just cut out the excess stuff when I pasted (thought it was irrelevant sorry).

Direct c/p

Public Sub btnSaveDetails_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveDetails.Click

Answer 6

If you are converting you can keep things the same.

However, if you make things new then don't use old vintage VB stuff. The Struct is an piece of memory on the Top Stack. Very cheap to use if it is less then 16bytes but very expensive as soon as it becomes more of that. 

Use then Classes.

However, in your case there is not even need for that. 

So you can create a class like this

    Public Class BookData
        Public Property Genres As List(Of String)
        Public Property Title As String
    End Class
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim Book As New BookData
        Book.Genres = New List(Of String) From {"Art", "History"}
        Book.Title = "Whatever"
    End Sub

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Success
Cor

Answer 7

Use this instead:

  ReDim LocalBookData.strGenres(5)

Answer 8

Try using ReDim instead of Dim.

Also, are you sure using a structure is the best way to go? Structures are value types, and you have declared an array within that type. If you copy the structure they will both share the same array with the same values (if you change the value in one structure, it will be reflected in the other structure).

I know you stated this is an example, but this is one of the fundamental points that should be discussed very early regarding structures, classes, value types, reference types.

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Stephen J Whiteley

Answer 9

Please do not double post... merging with original thread.

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Reed Kimble - "When you do things right, people won't be sure you've done anything at all"

Answer 10

...

Also, are you sure using a structure is the best way to go? Structures are value types, and you have declared an array within that type. If you copy the structure they will both share the same array with the same values (if you change the value in one structure, it will be reflected in the other structure).

I know you stated this is an example, but this is one of the fundamental points that should be discussed very early regarding structures, classes, value types, reference types.

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Stephen J Whiteley

Mike,

Please pay close attention to this...  you probably want this object defined as a class.

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Reed Kimble - "When you do things right, people won't be sure you've done anything at all"