vb.net - 未将对象引用设置为对象的实例 [VB.NET]

Question

 Public Class Form1
    Private Function AllEnabled(ByVal b As Boolean) As Boolean
        For i As Integer = 0 To 2
            Dim c As CheckBox = CType(Me.Controls("CheckBox" & i.ToString), CheckBox)
            c.Enabled = b
        Next
    End Function

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Call AllEnabled(False)
     End Sub
    End Class

在 b 中突出显示错误在 c.Enabled = b(你调用的对象是空的。)

但是当我使用 checkbox1.enabled = b而不是 c.enabled = b工作正常。

所以我看到错误不是 b对 ？

＆ 我怎样才能解决这个问题 ？

Answer 1

尝试这个:

For Each ctl In Me.Controls
  If TypeOf ctl Is CheckBox Then
   ctl.Enabled = b
  End If
Next