计数方向做循环 [英] Count direction do loop

问题描述

2个文本框
2个列表框
做while循环

我想在列表框中更改结果的方向，以根据文本框的输入进行更改.因此，如果Txtbox 1 = 0 Txtbox 2 = 10，则Listbox 1 = 1,3,5,7,9 Listbox 2-2,4,6,8,10；如果Txtbox 1 = 10 Txtbox 2 = 0，则Listbox 1 = 9 ，7,5,3,1列表框2 = 10,8,6,4,2

我要做什么

2 Textboxs
2 list boxs
do while loop

I want to change the direction of the result in the Listbox to change based on the input of the textbox. So if Txtbox 1 = 0 Txtbox 2 = 10 then Listbox 1 = 1,3,5,7,9 Listbox 2 - 2,4,6,8,10 and if Txtbox 1 = 10 Txtbox 2 = 0 then Listbox 1 = 9,7,5,3,1 Listbox 2 = 10,8,6,4,2

What i am trying to do

LowerB = CType(txtLB.Text, Integer)
            UpperB = CType(txtUB.Text, Integer)

            If LowerB < UpperB Then
                NumCounterI = CountUp
            Else
                NumCounterI = Countdown
            End If

            If LowerB < UpperB Then
                NumCounterI = LowerB

                Do While NumCounterI <= UpperB     
                    If NumCounterI <> 0 Then
                        If NumCounterI Mod 2 = EvenNumber Then
                            lstEvens.Items.Add(NumCounterI)
                        Else
                            lstOdds.Items.Add(NumCounterI)
                        End If
                    End If
                    NumCounterI += 1
                Loop

推荐答案

一个简单的解决方案:

A Simple Solution:

If LowerB < UpperB Then
    IncrementStep = 1
Else
    IncrementStep = -1
End If

For NumCounterI As Integer = LowerB To UpperB Step IncrementStep
        If NumCounterI Mod 2 = 0 Then
             ListBox1.Items.Add(NumCounterI.ToString())
        Else
               ListBox2.Items.Add(NumCounterI.ToString())
        End If
Next

rgds

rgds

我认为LINQ可以按如下方式使用来生成序列

I think LINQ can be used as follows to generate the sequences

Dim lb As Integer = 10
Dim ub As Integer = 0
Dim seq = Enumerable.Range(Math.Min(lb, ub), Math.Max(lb, ub) / 2)
Dim seq1 = If(lb > ub, seq.[Select](Function(s) s * 2 + 1).Reverse(), _
                    seq.[Select](Function(s) s * 2 + 1))
Dim seq2 = If(lb > ub, seq.[Select](Function(s) s * 2 + 2).Reverse(), _
                    seq.[Select](Function(s) s * 2 + 2))

根据OP [/Edit]的注释添加了使用do while loop的替代方法

Alternative using do while loop added as per the comment of OP [/Edit]

Dim lb = 10
Dim ub = 0
Dim list1 as new List(Of integer)
Dim list2 as new List(Of integer)
Dim inc = IF(lb < ub, 2, -2)
Dim seed1 = IF(lb < ub, 1, 9)
Dim seed2 = IF(lb < ub, 2, 10)
Dim ctr = 0
do while ctr < 5
    list1.Add(seed1 + ctr * inc)
    list2.Add(seed2 + ctr * inc)
    ctr += 1
loop

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