动态创建的按钮不会触发例程

Question

我有一个带有模板列的gridview：

<asp:UpdatePanel runat="server">  
 <ContentTemplate>  
  <asp:GridView ID="gridDay" runat="server" SkinID="gridviewSkinLight" AutoGenerateColumns="False" DataSourceID="DSAppointmentForDay">  
   <Columns>  
    <asp:BoundField DataField="TimeValue" HeaderText="" InsertVisible="False" ReadOnly="True" SortExpression="TimeValue" />  
    <asp:TemplateField HeaderText=" ">  
     <ItemStyle HorizontalAlign="Left" />  
    </asp:TemplateField>  
   </Columns>  
  </asp:GridView>  
 </ContentTemplate>  
 <Triggers>  
  <asp:AsyncPostBackTrigger ControlID="gridDay" />  
 </Triggers>  
</asp:UpdatePanel>  

在 RowDataBound 上，如果找到符合条件的数据，我会在单元格中创建按钮：

Dim cmdNew As New Button  
cmdNew.ID = "E" & dr("pkAppointment") & "|" & dr("ApptTopic")  
AddHandler cmdNew.Click, AddressOf mySub  
cmdNew.Text = dr("ApptTopic") & " >> " & dr("ApptLocation")  
cmdNew.ToolTip = "Topic: " & dr("ApptTopic") & vbLf &
                 "Location: " & dr("ApptLocation")  
e.Row.Cells(1).Controls.Add(cmdNew)  

到这里为止，一切都很好。这些按钮是在右侧单元格中创建的，带有所有的花里胡哨。

按钮应该调用的例程是：

Private Sub mySub(sender As System.Object, e As System.EventArgs)
    Try
        Dim btn As Button = DirectCast(sender, Button)
        MsgBox(btn.Text)

    Catch ex As Exception

    End Try
End Sub  

点击按钮的那一刻，页面刷新，所有创建的按钮都消失了，mySub 也没有被调用。

我错过了什么吗？

Answer 1

试试这个，

1) 添加一个脚本管理器，

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>

2）在gridview的OnRowCreated事件上创建按钮，将按钮注册为控件。

Dim cmdNew As New Button  
cmdNew.ID = "E" & dr("pkAppointment") & "|" & dr("ApptTopic")  
cmdNew.Text = dr("ApptTopic") & " >> " & dr("ApptLocation")  
cmdNew.ToolTip = "Topic: " & dr("ApptTopic") & vbLf &
                 "Location: " & dr("ApptLocation") 

ScriptManager1.RegisterAsyncPostBackControl(cmdNew) 
e.Row.Cells(1).Controls.Add(cmdNew)  

AddHandler cmdNew.Click, AddressOf mySub  
ScriptManager.GetCurrent(Me).RegisterAsyncPostBackControl(cmdNew)

更新（已测试）

1) 由于母版页中已有 ScriptManager，因此不需要新的。

2) 使用UpdatePanel，像这样

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowDataBound="CreateButtons" >
            <Columns>
                <asp:BoundField DataField="Code" /> <!-- example column -->
                <asp:BoundField DataField="Text" /> <!-- example column -->
                <asp:CommandField />
            </Columns>
        </asp:GridView>
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="GridView1"/>
    </Triggers>
</asp:UpdatePanel>

3) 在您的代码隐藏中，在OnRowDataBound 中创建按钮并在ScriptManager 中注册按钮，类似这样

Protected Sub CreateButtons(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim cmdNew As New Button
        cmdNew.ID = "Button" & e.Row.RowIndex
        cmdNew.Text = "Button" & e.Row.RowIndex
        cmdNew.ToolTip = "Button" & e.Row.RowIndex

        AddHandler cmdNew.Click, AddressOf CmdNewOnClick

        e.Row.Cells(2).Controls.Add(cmdNew)
        Dim myScriptManager As ScriptManager = Page.Master.FindControl("ScriptManager1")
        myScriptManager.RegisterAsyncPostBackControl(cmdNew)

    End If

End Sub

Private Sub CmdNewOnClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim buttonClicked As Button = sender
    Debug.WriteLine("-----------------------------------------------")
    Debug.WriteLine("Button clicked:" & buttonClicked.ID)
    Debug.WriteLine("-----------------------------------------------")
End Sub

一个演示项目可用here