Question

对于一个项目，我需要在运行时创建文本框，为此我使用了这段代码;

def send_test_email
  Merchant.test_production_email
  render json: nil, status: :ok
end

然后我可以使用这个For循环来循环它;

-------------------------------------
/var/log/aws-sqsd/default.log
-------------------------------------
2015-10-23T07:09:59Z message: sent to %[http://localhost:80/schedule/send_test_email]
2015-10-23T07:09:59Z http-err: 257fb276-d39e-4068-baf0-9106434674c5 (1) 502 - 0.004
2015-10-23T07:10:01Z message: sent to %[http://localhost:80/schedule/send_test_email]
2015-10-23T07:10:01Z http-err: 257fb276-d39e-4068-baf0-9106434674c5 (2) 502 - 0.007
2015-10-23T07:10:03Z message: sent to %[http://localhost:80/schedule/send_test_email]
2015-10-23T07:10:03Z http-err: 257fb276-d39e-4068-baf0-9106434674c5 (3) 502 - 0.004
2015-10-23T07:10:05Z message: sent to %[http://localhost:80/schedule/send_test_email]

但是，当代码到达该行时，这在理论上有效;

Dim AOP As Integer = GlobalVariables.AOP
Dim tb(11, 11) As TextBox
Dim LocationX As Integer
Dim LocationY As Integer
Dim count As Integer = 2

LocationX = 10
LocationY = 10
tb(1, 0).Name = "txtRoot"
tb(1, 0).Size = New Size(170, 20)
tb(1, 0).Location = New Point(LocationX, LocationY)
tb(1, 0).Visible = False

它返回错误'对象引用未设置为对象的实例' 我想知道是否还有这个？或者如果这种创建文本框的方式不可行？任何帮助将不胜感激。

Answer 1

您已初始化数组但未添加已初始化的TextBoxes，该数组目前仅包含Nothing。另请注意，数组基于零，因此第一个TextBox位于tb(0, 0)。

For i As Int32 = 0 To tb.GetLength(0) - 1
    For ii As Int32 = 0 To tb.GetLength(1) - 1
        tb(i, ii) = New TextBox()
        tb(i, ii).Visible = False
        ' .... '
    Next
Next

现在全部都已初始化。

如何在VB中运行时创建文本框时停止“对象引用未设置为对象的实例”

1 个答案: