如何将3个列表框项添加到一个列表框中 [英] how to Add 3 listboxes items into one listbox

问题描述

你好

我有3个列表框，每个列表框包含很多项目（listbox1，listbox2，listbox3）

和另一个空列表框（listbox4）

我试图将前三个列表框项目添加到第4个列表框中



ex：）listbox1第一项是'A'，listbox2第一项是'b'，listbox3第一项目是'c'

现在listbox4第一项必须是Abc



问题是它的工作但保持循环项目。 br />


这是我的代码：

Hello
I have 3 listboxes each one contains many items (listbox1 , listbox2,listbox3)
and another empty listbox (listbox4)
im trying to add first three listboxes items into the 4th listbox

ex: ) listbox1 first items is 'A' , listbox2 first items is 'b' , listbox3 first items is 'c'
now listbox4 first item must be "Abc"

The problem is Its work but keep loop the items.

here is my code :

For i = 1 To ListBox1.Items.Count - 1

           For j = i To ListBox2.Items.Count - 1

               For k = j To ListBox3.Items.Count - 1

                   ListBox4.Items.Add(ListBox1.Items(j).ToString + ListBox2.Items(j).ToString + ListBox3.Items(k).ToString)

                   Exit For
               Next
           Next
       Next

推荐答案

使用Linq的替代方案

An alternative using Linq

Dim l1 As List(Of String) = ListBox1.Items.Cast(Of String)().ToList()
Dim l2 As List(Of String) = ListBox2.Items.Cast(Of String)().ToList()
Dim l3 As List(Of String) = ListBox3.Items.Cast(Of String)().ToList()

Dim l4 As List(Of String) = New List(Of String)(l1)
l4.AddRange(l2)
l4.AddRange(l3)

ListBox4.DataSource = l4

如果所有列表框都有相同数量的项目，您的代码可能会起作用。考虑这种方法：

Your code might work if all the list boxes had equal number of items. Consider this approach:

Dim list As New List(Of ListBox)
list.AddRange({ListBox1, ListBox2, ListBox3})
For Each l As ListBox In list
    For Each s As String In l.Items
        ListBox4.Items.Add(s)
    Next
Next

希望这会有所帮助。



regs

Hope this helps.

regs

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