我们可以在函数 vb.net 中返回两个变量值吗？

Can we return two variable value in function vb.net?

提问by Ahad Murtaza

can we return two values in function vb.net

我们可以在函数 vb.net 中返回两个值吗

Public Function jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer) As String

    For i As Integer = 0 To arr.GetUpperBound(0)
        For j As Integer = 0 To arr(i).GetUpperBound(0)
            If arr(i)(j) = keyvalue Then
                Return i j
            End If
        Next
    Next

End Function`

回答by Enigmativity

I can offer you three ways of doing it.

我可以为您提供三种方法。

First is to use Tuple(Of Integer, Integer).

首先是使用Tuple(Of Integer, Integer).

Public Function jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer) As Tuple(Of Integer, Integer)
    For i As Integer = 0 To arr.GetUpperBound(0)
        For j As Integer = 0 To arr(i).GetUpperBound(0)
            If arr(i)(j) = keyvalue Then
                Return Tuple.Create(i, j)
            End If
        Next
    Next
End Function

The second is to define you own return class.

第二个是定义你自己的返回类。

Public Function jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer) As Pair
    For i As Integer = 0 To arr.GetUpperBound(0)
        For j As Integer = 0 To arr(i).GetUpperBound(0)
            If arr(i)(j) = keyvalue Then
                Return New Pair(i, j)
            End If
        Next
    Next
End Function

Public NotInheritable Class Pair
    Implements IEquatable(Of Pair)

    Private ReadOnly _I As Integer

    Private ReadOnly _J As Integer

    Public ReadOnly Property I As Integer
        Get
            Return _I
        End Get
    End Property

    Public ReadOnly Property J As Integer
        Get
            Return _J
        End Get
    End Property

    Public Sub New(I As Integer, J As Integer)
        _I = I
        _J = J
    End Sub

    Public Overrides Function Equals(obj As Object) As Boolean
        If TypeOf obj Is Pair
            Return Equals(DirectCast(obj, Pair))
        End If

        Return False
    End Function

    Public Overloads Function Equals(obj As Pair) As Boolean Implements IEquatable(Of Pair).Equals
        If obj Is Nothing
            Return False
        End If

        If Not EqualityComparer(Of Integer).[Default].Equals(_I, obj._I)
            Return False
        End If

        If Not EqualityComparer(Of Integer).[Default].Equals(_J, obj._J)
            Return False
        End If

        Return True
    End Function

    Public Overrides Function GetHashCode() As Integer
        Dim hash As Integer = 0
        hash = hash Xor EqualityComparer(Of Integer).[Default].GetHashCode(_I)
        hash = hash Xor EqualityComparer(Of Integer).[Default].GetHashCode(_J)
        Return hash
    End Function

    Public Overrides Function ToString() As String
        Return [String].Format("{{ I = {0}, J = {1} }}", _I, _J)
    End Function
End Class

The third, and probably the most interesting way is to pass a return delegate.

第三种，可能也是最有趣的方式是传递返回委托。

Public Sub jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer, ByVal [return] As Action(Of Integer, Integer))
    For i As Integer = 0 To arr.GetUpperBound(0)
        For j As Integer = 0 To arr(i).GetUpperBound(0)
            If arr(i)(j) = keyvalue Then
                [return](i, j)
            End If
        Next
    Next
End Sub

This method changes from a Functionto Suband the [return] As Action(Of Integer, Integer)allows multiple return values of multiple pairs.

此方法从一个Function到Sub并[return] As Action(Of Integer, Integer)允许多个对的多个返回值。

You could even couple this with the Pairclass and do this:

您甚至可以将其与Pair课程结合起来并执行以下操作：

Public Sub jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer, ByVal [return] As Action(Of Pair))
    For i As Integer = 0 To arr.GetUpperBound(0)
        For j As Integer = 0 To arr(i).GetUpperBound(0)
            If arr(i)(j) = keyvalue Then
                [return](New Pair(i, j))
            End If
        Next
    Next
End Sub

回答by Rob

Here are two approaches:

这里有两种方法：

The first and simplest approach is to change your function to a subroutine as follows:

第一种也是最简单的方法是将您的函数更改为子程序，如下所示：

Public Sub jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer, ByRef I as Integer, ByRef J as Integer)

and in the subroutine initialize j and i to -1 before the for loop, and where you currently have the return statement just add in a Exit For

并在子例程中，在 for 循环之前将 j 和 i 初始化为 -1，并且您当前拥有 return 语句的地方只需添加 Exit For

The Second approach is as follows:

第二种方法如下：

In the function return the values as follows:

在函数中返回值如下：

Return i.tostring & "|" & j.tostring

and in the calling program

并在调用程序中

Dim ReturnValues as String = jaggedarr(...)
Dim EachReturnValue() as string = ReturnValue.split("|")
Dim FirstValue as integer = Ctype(EachReturnValue(0), Integer)
Dim SecondValue as integer = Ctype(EachReturnValue(1), Integer)

回答by Zohar Peled

From what I understand you want the function to return the indexes of the first appearance of the value in the jagged array.
One way to do it is return a Tuple:

据我了解，您希望该函数返回该值在锯齿状数组中第一次出现的索引。
一种方法是返回一个元组：

Public Function jaggedarr(ByRef arr()() As Integer, ByVal keyvalue As Integer) As Tuple(Of Int, Int)

For i As Integer = 0 To arr.GetUpperBound(0)
    For j As Integer = 0 To arr(i).GetUpperBound(0)
        If arr(i)(j) = keyvalue Then
            Return new Tuple(i, j)
        End If
    Next
Next
'' if no string was found:
return new Tuple(-1,-1) '' or you can return Nothing...
End Function