说明: 执行当前 Web 请求期间,出现未处理的异常。请检查堆栈跟踪信息,以了解有关该错误以及代码中导致错误的出处的详细信息。 异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。源错误:
行 46: Dim i, NumPoints As Integer
行 47: NumPoints = myCount.ExecuteScalar
行 48: ReDim ax(NumPoints - 1)
行 49: ReDim aY(NumPoints - 1)
行 50: While myOleDbDataReader.Read
源文件: C:\Inetpub\wwwroot\erp\erp\WebForm5.aspx.vb 行: 48 堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
erp.webform5.Page_Load(Object sender, EventArgs e) in C:\Inetpub\wwwroot\erp\erp\WebForm5.aspx.vb:48
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Page.ProcessRequestMain() +731
以下是我的代码:
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim str As String = " SELECT date,h2 FROM History_sp"
Dim CountText As String = "SELECT COUNT(*) From History_sp" Dim conn1 As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\spdb.mdb;" & _
"User ID=Admin;" & _
"Password="
Dim conn As OleDbConnection = New OleDbConnection(conn1)
Dim mycommand As OleDbCommand = New OleDbCommand(str, conn)
Dim myCount As OleDbCommand = New OleDbCommand(CountText, conn)
conn.Open()
Dim ax()
Dim ay()
Dim myOleDbDataReader As OleDbDataReader = mycommand.ExecuteReader()
Dim i, NumPoints As Integer
NumPoints = myCount.ExecuteScalar
ReDim ax(NumPoints - 1)
ReDim aY(NumPoints - 1)
While myOleDbDataReader.Read
For i = 0 To NumPoints - 1
ax(i) = myOleDbDataReader.GetValue(1)
ay(i) = myOleDbDataReader.GetValue(0)
i = i + 1
Next
End While
myOleDbDataReader.Close()
conn.Close()
请问是哪里的问题?
行 46: Dim i, NumPoints As Integer
行 47: NumPoints = myCount.ExecuteScalar
行 48: ReDim ax(NumPoints - 1)
行 49: ReDim aY(NumPoints - 1)
行 50: While myOleDbDataReader.Read
源文件: C:\Inetpub\wwwroot\erp\erp\WebForm5.aspx.vb 行: 48 堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
erp.webform5.Page_Load(Object sender, EventArgs e) in C:\Inetpub\wwwroot\erp\erp\WebForm5.aspx.vb:48
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Page.ProcessRequestMain() +731
以下是我的代码:
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim str As String = " SELECT date,h2 FROM History_sp"
Dim CountText As String = "SELECT COUNT(*) From History_sp" Dim conn1 As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\spdb.mdb;" & _
"User ID=Admin;" & _
"Password="
Dim conn As OleDbConnection = New OleDbConnection(conn1)
Dim mycommand As OleDbCommand = New OleDbCommand(str, conn)
Dim myCount As OleDbCommand = New OleDbCommand(CountText, conn)
conn.Open()
Dim ax()
Dim ay()
Dim myOleDbDataReader As OleDbDataReader = mycommand.ExecuteReader()
Dim i, NumPoints As Integer
NumPoints = myCount.ExecuteScalar
ReDim ax(NumPoints - 1)
ReDim aY(NumPoints - 1)
While myOleDbDataReader.Read
For i = 0 To NumPoints - 1
ax(i) = myOleDbDataReader.GetValue(1)
ay(i) = myOleDbDataReader.GetValue(0)
i = i + 1
Next
End While
myOleDbDataReader.Close()
conn.Close()
请问是哪里的问题?
解决方案 »
- Sql语句怎么写啊?
- 关于.net petshop4.0
- ajaxpro目前最新爱是ajax.2.dll吗?
- 求救,用.net动态生成html页面的问题,很郁闷
- 在asp.net中加入背景音乐的问题
- asp.net的csharp代码里面如何获取web.config里面的authentication mode的配置?
- email 发送报错 不允许使用邮箱名称 我用的是smtp.163.com的 怎么解决???
- 请教asp.net上传时,可不可以在客户端判断文件大小?如果可以,怎么做?
- 请教IEWebControls 是个什么东东?
- 我的Web程序在运行时有时出错,可不知道怎么就好了,纳闷+郁闷!!!
- FreeTextBox.dll 错误..请高手指点
- 如何将一张图片压缩?
这行你单步调试下,有可能是返回了一个null
NumPoints 未获得值