vb.net 未将对象引用设置到对象的实例。
Public Class Form1
Dim a() As Integer
Sub shuru(ByRef b() As Integer)
Dim n%, i%
n = InputBox("请输入要比较的数字或字母的个数")
For i = 0 To n - 1
b(i) = InputBox("输入第" & i + 1 & " 个数字")
MsgBox(b(i))
Next

End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Call shuru(a)

End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim i%, j%, k%, temp%
For i = 0 To UBound(a)
For j = 0 To j - i - 1
If (a(j) < a(j + 1)) Then
temp = a(j)
a(i) = a(j + 1)
a(j + 1) = temp

End If
Next
For k = 0 To UBound(a)
Label1.Text &= a(k) & ","
Next
Label1.Text &= vbCrLf
Next
For i = 0 To UBound(a)
TextBox1.Text &= a(i) & ","
Next
End Sub
End Class




未将对象引用设置到对象的实例。


[解决办法]

VB.NET code

        k = i 'i   '实际的可用串口总数        If k > 0 Then    '有一个以上串口就比较，出错则不管            Try                Dim t As Integer = 0                For i = 0 To k - 1                    For j = i + 1 To k - 1                        If portlis(j) < portlis(i) Then  '保证小的在数组的前面，排序                            t = portlis(j)                            portlis(j) = portlis(i)                            portlis(i) = t                        End If                    Next j                Next i                ComboBoxPortName.Items.Clear() '清空列表                For i = 0 To k - 1                    ComboBoxPortName.Items.Add("COM" + portlis(i).ToString)       '显示可用串口                Next i                If ComboBoxPortName.Items.Count > 0 Then                    ComboBoxPortName.SelectedIndex = 0                    '     有可用串口，可以打开操作                End If            Catch 'ex As Exception            End Try            ' Else            ' MsgBox("无可用串口！")        End If    '这是关于串口的冒泡排序法，作用将串口按数字大小排序，你    '可以参考下相关的部分
[解决办法]
 
VB.NET code
 ' n = InputBox("请输入要比较的数字或字母的个数") ReDim b(n)    '!!!!! please add this here ，HA HA