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  1. #1
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    multiple declaration

    ok this sounds dumb but i just wanted to do something simple

    Code:
    dim this, that, alll, duno, etc, anddd, more as integer
    this = that = etc = more = 6
    doesn't work, is there a way to do this in vb?

  2. #2
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    Re: multiple declaration

    Quote Originally Posted by pacerier View Post
    ok this sounds dumb but i just wanted to do something simple

    Code:
    dim this, that, alll, duno, etc, anddd, more as integer
    this = that = etc = more = 6
    doesn't work, is there a way to do this in vb?

    Nope. Plus, in the DIM statement, only more is an Integer. Everything in RED is actually a VARIANT, and slower to use.

    Declare each variable's type. You can include multiple per statement.

    Assigning a value to more than one item isn't allowed.

    Code:
    Dim this as Integer, that as Integer, etc as Integer
    this = 6 : that = 6 : etc = 6 : more = 6
    David

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  3. #3
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    Re: multiple declaration

    Doing this :
    Code:
    Dim this As Integer, that As Integer, alll As Integer, duno As Integer, etc As Integer, anddd As Integer, more As Integer
    more = 6
    etc = 7
    that = 5
    
    this = that = etc = more
    
    MsgBox that
    Would give me 5

    Doing this :
    Code:
    Private Sub Form_Load()
    Dim this As Integer, that As Integer, alll As Integer, duno As Integer, etc As Integer, anddd As Integer, more As Integer
    more = 6
    etc = 7
    that = 5
    
    that = etc = more
    MsgBox this
    End Sub
    Would give 0
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  4. #4
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    Re: multiple declaration

    An expression A=B=C will evaluate like this:
    A is assigned the result of B=C, which is a boolean expression like in the if statement.
    If B equals C then A will become True, if B is different to C, A becomes False.
    If A however is not a boolean, but an integer, it becomes -1 for true and 0 for false.
    A multi assignment statement will likewise evaluate:
    A=B=C=D=6.
    If all variables are assumed 0, then D=6 will be false, so we have
    A=B=C=0
    C is 0 will be true, being -1 in an integer representation, so we have
    A=B=-1
    So B=-1 becomes 0 (false) for B being 0. This reduces the evaluation to
    A=0
    That's what the result should turn out.

  5. #5
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    Re: multiple declaration

    The whole point I'm still trying to figure out as well, is why is this even allowed in the compiler. Surely it should be ¿
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  6. #6
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    Re: multiple declaration

    [Moved to VB.NET]
    Sorry about bumping the thread, but OP is actually asking a question related to VB.NET. I have moved few of the threads to VB.NET forum earlier that were posted by the same member.

    So in vb.net dim this, that, alll, duno, etc, anddd, more as integer would declare all of them as integers.

  7. #7
    Join Date
    Oct 2009
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    28

    Re: multiple declaration

    hey sry what exactly is the difference between vb and vb.net?

    im using microsoft visual basic 2008, is that vb.net?

  8. #8
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    Re: multiple declaration

    Quote Originally Posted by HanneSThEGreaT View Post
    The whole point I'm still trying to figure out as well, is why is this even allowed in the compiler. Surely it should be
    The reason it is allowed is because it is correct syntax.

    As WoF explains, VB.NET (possible VB as well?) treat the = after the first assignment as boolean comparisons and not as assignments.
    It is a syntax silliness in my book doing nothing but add confusion, but it is perfectly legal VB.NET syntax.

  9. #9
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    Oct 2009
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    Re: multiple declaration

    what's the difference between vb 6 and vb.net? is vb.net a new version of vb6?

  10. #10
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    Re: multiple declaration

    Yes, that is VB.NET, in this case

    This :
    http://www.codeguru.com/forum/forumdisplay.php?f=12

    Is the VB.NET Forum.

    Where you posted was for VB 6, mainly
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  11. #11
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    Re: multiple declaration

    Hannes, the thread is already moved to VB.NET (Post #6)

  12. #12
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    Re: multiple declaration

    Quote Originally Posted by Shuja Ali View Post
    Hannes, the thread is already moved to VB.NET (Post #6)
    Thanx for pointing that out! I need glasses!
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  13. #13
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    Re: multiple declaration

    There are a lot of articles in internet about the difference between vb6 and vb.net.
    Check this link
    http://www.thescarms.com/vbasic/vb6vsvbnet.aspx

  14. #14
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    Re: multiple declaration

    To explain why is the syntax A=B=C is logically allowed:
    It is simply to store the result of a comparison.
    B=C, when used as a term, is a boolean expression which evaluates to true or false. (Or will be treated as-1 and 0, if the other terms are numerical).
    A=B=C replaces the statement If B=C Then A=True Else A=False
    Likewise you can do A=B>C or A=B<=C to keep results of comparisons in A.
    A=B=C=D must therefore be syntactically correct, although it does not make much sense.

    I use this kind of conditional often when having to switch an array of controls on and off.
    Say you have an array of 10 checkboxes and you want box 0 to 4 enabled, box 5 to 9 disabled, not knowing what their current state is.
    Code:
    For i=0 to 9
       chkBox(i).Enabled = i<5
    Next

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