I know there's no straightforward way for multiple assignment of function in VB
, but there's my solution - is it good, how would you do it better?
What I need (how would I do it in python, just an example)
def foo(a) ' function with multiple output
return int(a), int(a)+1
FloorOfA, CeilOfA = foo(a) 'now the assignment of results
How I do it in VB:
Public Function foo(ByVal nA As Integer) As Integer() ' function with multiple output
Return {CInt(nA),CInt(nA)+1}
End Function
Dim Output As Integer() = foo(nA) 'now the assignment of results
Dim FloorOfA As Integer = Output(0)
Dim CeilOfA As Integer = Output(1)
A function in VB.NET can only return one value—this can be a value type or a reference type (like a Class). But one value is not always sufficient. With ByRef arguments, we can set multiple output values. And with a structure like KeyValuePair (or a class like Tuple) we can return multiple values as one.
For future readers, VB.NET 2017 and above now supports value tuples as a language feature. You declare your function as follows:
Function ColorToHSV(clr As System.Drawing.Color) As (hue As Double, saturation As Double, value As Double)
Dim max As Integer = Math.Max(clr.R, Math.Max(clr.G, clr.B))
Dim min As Integer = Math.Min(clr.R, Math.Min(clr.G, clr.B))
Dim h = clr.GetHue()
Dim s = If((max = 0), 0, 1.0 - (1.0 * min / max))
Dim v = max / 255.0
Return (h, s, v)
End Function
And you call it like this:
Dim MyHSVColor = ColorToHSV(clr)
MsgBox(MyHSVColor.hue)
Note how VB.NET creates public property named hue
inferred from the return type of the called function. Intellisense too works properly for these members.
Note however that you need to target .NET Framework 4.7 for this to work. Alternately you can install System.ValueTuple
(available as NuGet package) in your project to take advantage of this feature.
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