Private Sub CoBox1_TextChanged(sender As Object, e As EventArgs) Handles CoBox1.TextChanged
'獲取輸入的字符串
Dim text As String = CoBox1.Text.Trim()
'用以記錄匹配字符串的個數(shù)
Dim index As Integer = 0
Dim listBox1 As New ListBox
' list_Pd是定義的全局布爾變量，用于判斷是否創(chuàng)建了listbox控件
If list_pd Then '如果已經(jīng)創(chuàng)建
For Each contr As Control In Me.Controls '遍歷窗體中的所有控件，尋找創(chuàng)建的listbox控件
If contr.Name = "list" Then
listBox1 = CType(contr, ListBox)
End If
Next
Else '如果沒有創(chuàng)建，則調(diào)用Custom_ListBox()函數(shù)創(chuàng)建
listBox1 = Custom_ListBox(CoBox1)
End If
'將listbox 控件所有項清空
listBox1.Items.Clear()
'將查詢的結(jié)果添加到listbox 的items 中
For Each Str As String In CoBox1.Items
'將所有的字符串全部轉(zhuǎn)化為小寫再判斷，這樣輸入就不用分大小寫了
If Not text = "" And Str.ToLower.Contains(text.ToLower) Then
index += 1
listBox1.Items.Add(Str)
End If
Next
'判斷符合條件的項的個數(shù)，
If index = 1 Then
CoBox1.Text = listBox1.Items(0)
listBox1.Visible = False
ElseIf index > 1 Then
listBox1.Visible = True
Else
listBox1.Visible = False
End If
listBox1.BringToFront()
End Sub
Private Function Custom_ListBox(ByVal CoBox1 As ComboBox) As ListBox
Dim Listbox As New ListBox
Dim point As Point
point.X = CoBox1.Location.X
point.Y = CoBox1.Location.Y + CoBox1.Height
With Listbox
.Name = "list" '設(shè)置控件名稱
.Location = point '設(shè)置控件的位置，放在combobox的下面
.Width = CoBox1.Width '控件的寬度，與combobox的寬一樣
.Height = CoBox1.Height * (CoBox1.Items.Count + 1) '高度
.Items.Clear()
.Visible = False
End With
AddHandler Listbox.Click, AddressOf ListBox_Click '添加點擊事件 ListBox_Click（）
Me.Controls.Add(Listbox) '這步重要 將控件添加到窗體中。沒有這句將不會顯示listbox控件
list_pd = True
Return Listbox
End Function
Private Sub ListBox_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
CType(sender, ListBox).Visible = False
CoBox1.Text = CType(sender, ListBox).SelectedItem
End Sub
