Multiple Variables

Question

Is there a way to give a value to multiple variables (integers in this case), instead of all at once?

For instance, I have Dim aceVal, twoVal, threeVal, fourVa

Answer 1

I know this is an old thread, however I've just run into a similar issue myself - here's how I did it (I am only dealing with 4 values

Private Sub SetFalse(ByRef first As Boolean, Optional ByRef second As Boolean = False, Optional ByRef third As Boolean = False, Optional ByRef fourth As Boolean = False)
    first = False
    second = False
    third = False
    fourth = False
End Sub

this can be easily adapted, by making the first variable the required value (this code also looks a bit daft because I have to provide a default which can only be true or false, but obviously with integers or something it looks more meaningful.)

Answer 2

I thought the multiple assignment feature was so cool in C# that I wrote a VB extension method (Assign) to do the same thing. The semantics are pretty easy to follow; you just call Assign on any value to assign it to multiple other variables i.e.

Call True.Assign(b1, b2, b3)
Call 4.1.Assign(d1, d2, d3)

etc...

Here's the code:

Imports System.Runtime.CompilerServices


Namespace Utility
    Public Module MultiAssignExtensionMethod
        ' Multiply assign the same value to 1 (required) or more variables
        <Extension()> _
        Public Function Assign(Of T)(this As T, ByRef first As T, Optional ByRef second As T = Nothing, Optional ByRef third As T = Nothing,
                                    Optional ByRef forth As T = Nothing, Optional ByRef fifth As T = Nothing, Optional ByRef sixth As T = Nothing,
                                    Optional ByRef seventh As T = Nothing, Optional ByRef eighth As T = Nothing, Optional ByRef nineth As T = Nothing,
                                    Optional ByRef tenth As T = Nothing) As T
                            ' I would LIKE to do this as a ParamArray, but it doesn't allow references for basic types....grrr
            first = this
            second = this
            third = this
            forth = this
            fifth = this
            sixth = this
            seventh = this
            eighth = this
            nineth = this
            tenth = this

            Return this     ' For use as assignment and evaluation as Function parameter
        End Function
    End Module
End Namespace

Answer 3

If you want to keep it on one line then you can do it like this

Dim m1 As String = "false", m2 As String = "false", m3 As String = "false" 
'etc..

Answer 4

You could use an array/dictionary like so:

Dictionary myValues = new Dictionary();

myValues.Add("FirstVal", 1);
myValues.Add("SecondVal", -1);
myValues.Add("ThirdVal", 1);

You could then write a simple function:

public updateMyValues(string[] myKeys, int myValue)
{
     foreach (string s in myKeys)
        {
            myValues[s] = myValue;
        }
}

And finally when your list box changes you could just call the function to update the variables you want like so:

upDateMyValues({"FirstVal", "ThirdVal"}, -1);

Hope this helps.

*Edit: I know it's in C#, but it's easily portable to VB.

Answer 5

I really don't mean to be a jerk, but is there any reason why you can't just do:

threeVal = -1
fourVal = -1
sixVal = -1

Answer 6

There is no way in vb.net to assign them all on one line like threeVal=fourVal=SixVal.

If you need all these variables then one line at a time is the way. I would suggest if -1 is going to be used a lot then create a constant for it and assign the var's to the constant.

I would also consider using an array or collection to store all your values if possible and work with them in order for setting / retrieving their values. You then won't have to have 60 variables littered all in your code. Array and/or collection would be a little cleaner.