Question

我正在尝试在包含文本框和下拉列表的页面上循环控制并清除它们。

当我调试时，parent是当前页面，value等于ASP.nameOfCurrentpage_aspx和 Type等于system.web.ui.page，但c的值为ASP.site_master，类型为system.web.ui.control。我还放入x来查看它找到了多少控件，即使页面上有15个左右的文本框，x也会返回1。有没有办法可以强制c获得ASP.nameOfCurrentpage_aspx的值？或者这不是我的问题？任何帮助表示赞赏。

Protected Sub btnClear_Click(sender as Object, e as System.eventargs) Handles btnClear.Click
   ClearForm(Page)

End Sub

Public Sub ClearForm(ByRef Parent As Control)
    Dim c As Control
    Dim x As Integer = Parent.Controls.Count
    For Each c In Parent.Controls
        If c.GetType.ToString = "System.Web.UI.HtmlControls.HtmlForm" Then
            ClearForm(c)
        ElseIf c.GetType() Is GetType(TextBox) Then
            'is it a Text Box?
            Dim t As TextBox = c
            t.Text = ""
        ElseIf c.GetType() Is GetType(DropDownList) Then
            'is it a dropdown list?
            Dim d As DropDownList = c
            d.ClearSelection()
        End If
    Next

End Sub

Answer 1

HTMLForm控件可能是嵌套的，可能是在MasterPage下。要么完全递归函数，要么在If语句中添加一个查找母版页的子句。这是断点和观察窗是黄金的地方。

例如：

ElseIf c.GetType.ToString = "ASP.MasterPageName_Master" Then
   ClearForm(c)

Answer 2

谢谢大家的帮助。我没有尝试所有的答案，但我用它们的想法。这就是我们在工作中提出的，它可以找到并清除页面上的所有控件。我们必须找到链接到主站点（cph）的内容占位符。再次感谢所有的建议。

Public Sub ClearForm(ByRef Parent As Control)
    Dim cph As System.Web.UI.WebControls.ContentPlaceHolder = Master.FindControl("MainBody")
    Dim c As Control
    Dim x As Integer = Parent.Controls.Count
    For Each c In cph.Controls
        If c.GetType.ToString = "System.Web.UI.HtmlControls.HtmlForm" Then
            ClearForm(c)
        ElseIf c.GetType() Is GetType(TextBox) Then
            'is it a Text Box?
            Dim t As TextBox = c
            t.Text = ""
        ElseIf c.GetType() Is GetType(DropDownList) Then
            'is it a dropdown list?
            Dim d As DropDownList = c
            d.ClearSelection()
        End If
    Next

End Sub

Answer 3

自从我使用控件编写.NET中的任何内容以来，已经有一段时间了，MVC愚蠢地破坏了我，或者使用VB.NET ......

但是我想你可能需要通过一堆控件来递归：

Protected Sub btnClear_Click(sender as Object, e as System.eventargs) Handles btnClear.Click
   ClearForm(Page)

End Sub

Public Sub ClearForm(ByRef Parent As Control)
    Dim c As Control
    Dim x As Integer = Parent.Controls.Count
    For Each c In Parent.Controls
        If c.GetType.ToString = "System.Web.UI.HtmlControls.HtmlForm" Then
            ClearForm(c)
        ElseIf c.GetType() Is GetType(TextBox) Then
            'is it a Text Box?
            Dim t As TextBox = c
            t.Text = ""
        ElseIf c.GetType() Is GetType(DropDownList) Then
            'is it a dropdown list?
            Dim d As DropDownList = c
            d.ClearSelection()
        ElseIf c.Controls != null ' Does VB.NET support nulls? I forget
            ClearForm(c.Controls)
        End If
    Next

End Sub

vb.net循环控制不起作用

3 个答案: