Asp.net 嵌套中继器错误：对象引用未设置为对象的实例

我正在使用一些以前用于嵌套listview的代码，并试图使其与嵌套的中继器一起工作，但我遇到了一个错误

System.NullReferenceException:对象引用未设置为对象的实例

.aspx

我必须为中继器做些不同的事情吗

谢谢你的帮助

---

J.

它的标题行是第一次，因此您无法获得内部中继器控件。对项目类型应用检查，如下所示

Protected Sub reMainNav_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles reMainNav.ItemDataBound

 If e.Item.ItemType == ListItemType.Item OrElse e.Item.ItemType == ListItemType.AlternatingItem Then

    Dim rowView As System.Data.DataRowView
    rowView = CType(e.Item.DataItem, System.Data.DataRowView)

    'database connection from web.config file
    Dim synergySQL As SqlConnection = New SqlConnection()
    synergySQL.ConnectionString = ConfigurationManager.ConnectionStrings("connSynergy").ConnectionString()

    'check if personal section complete
    Dim cmdSubNav As SqlCommand = New SqlCommand()
    cmdSubNav.Connection = synergySQL
    cmdSubNav.CommandText = "SELECT * FROM [subNavigation] WHERE [parentId] = " & rowView("id") & " ORDER BY [orderNo]"
    cmdSubNav.CommandType = CommandType.Text
    'data adapter
    Dim daSubNav As SqlDataAdapter = New SqlDataAdapter
    daSubNav.SelectCommand = cmdSubNav
    'data set
    Dim dsSubNav As DataSet = New DataSet()
    daSubNav.Fill(dsSubNav, "SubNav")

    Dim iSchedule As Integer
    iSchedule = dsSubNav.Tables(0).Rows.Count

    Dim reSubNav As Repeater = CType(e.Item.FindControl("reSubNav"), Repeater)
    reSubNav.DataSource = dsSubNav
    reSubNav.DataBind()

    synergySQL.Close()

End If

End Sub

---

调试代码。有关错误的详细信息，请处理异常。。！！感谢Umar，我正在尝试类似的方法，但无法获得正确的语法。我将如何解决此问题：。谢谢

    Protected Sub reMainNav_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles reMainNav.ItemDataBound

    Dim rowView As System.Data.DataRowView
    rowView = CType(e.Item.DataItem, System.Data.DataRowView)

    'database connection from web.config file
    Dim synergySQL As SqlConnection = New SqlConnection()
    synergySQL.ConnectionString = ConfigurationManager.ConnectionStrings("connSynergy").ConnectionString()

    'check if personal section complete
    Dim cmdSubNav As SqlCommand = New SqlCommand()
    cmdSubNav.Connection = synergySQL
    cmdSubNav.CommandText = "SELECT * FROM [subNavigation] WHERE [parentId] = " & rowView("id") & " ORDER BY [orderNo]"
    cmdSubNav.CommandType = CommandType.Text
    'data adapter
    Dim daSubNav As SqlDataAdapter = New SqlDataAdapter
    daSubNav.SelectCommand = cmdSubNav
    'data set
    Dim dsSubNav As DataSet = New DataSet()
    daSubNav.Fill(dsSubNav, "SubNav")

    Dim iSchedule As Integer
    iSchedule = dsSubNav.Tables(0).Rows.Count

    Dim reSubNav As Repeater = CType(e.Item.FindControl("reSubNav"), Repeater)
    reSubNav.DataSource = dsSubNav
    reSubNav.DataBind()

    synergySQL.Close()

End Sub

Protected Sub reMainNav_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles reMainNav.ItemDataBound

 If e.Item.ItemType == ListItemType.Item OrElse e.Item.ItemType == ListItemType.AlternatingItem Then

    Dim rowView As System.Data.DataRowView
    rowView = CType(e.Item.DataItem, System.Data.DataRowView)

    'database connection from web.config file
    Dim synergySQL As SqlConnection = New SqlConnection()
    synergySQL.ConnectionString = ConfigurationManager.ConnectionStrings("connSynergy").ConnectionString()

    'check if personal section complete
    Dim cmdSubNav As SqlCommand = New SqlCommand()
    cmdSubNav.Connection = synergySQL
    cmdSubNav.CommandText = "SELECT * FROM [subNavigation] WHERE [parentId] = " & rowView("id") & " ORDER BY [orderNo]"
    cmdSubNav.CommandType = CommandType.Text
    'data adapter
    Dim daSubNav As SqlDataAdapter = New SqlDataAdapter
    daSubNav.SelectCommand = cmdSubNav
    'data set
    Dim dsSubNav As DataSet = New DataSet()
    daSubNav.Fill(dsSubNav, "SubNav")

    Dim iSchedule As Integer
    iSchedule = dsSubNav.Tables(0).Rows.Count

    Dim reSubNav As Repeater = CType(e.Item.FindControl("reSubNav"), Repeater)
    reSubNav.DataSource = dsSubNav
    reSubNav.DataBind()

    synergySQL.Close()

End If

End Sub