用户控制按钮单击事件未引发

我有一个动态添加到页面的用户控件。当我单击该用户控件上的按钮时:

1. 没有引发按钮单击事件
2. 该页发回
3. 用户控件已从页中删除

下面是我的用户控件上的按钮单击事件:

 Protected Sub btnAddAttribute_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddAttribute.Click
      Try
           Dim attrName As String = txtAddAttributeName.Text
           Dim attrValue As String = txtAddAttributeValue.Text

           'ADD ATTRIBUTE TO ATTRIBUTE TABLE
           putSQLData("INSERT INTO OD_Attribute_Values (AttributeName, AttributeValue) VALUES('" & attrValue & "', '" & attrName & "'")

           'ADD ATTRIBUTE TO PRODUCT DATA FOR THIS PRODUCT
           putSQLData("UPDATE OD_Product_Data SET VariantMapping = VariantMapping + ' | " & attrName & ":" & attrValue & "' WHERE SKU = '" & SelectedSKU & "'")

           'ADD NEW ctrlAttribute TO PARENT PLACEHOLDER AND SET VALUES
           Dim newAttr As New AttributeControl
           newAttr.AttributeName = attrName
           newAttr.AttributeValue = attrValue
           Page.Controls.AddAt(Page.FindControl("phAttributes").ClientID, newAttr)

           'REMOVE THIS CONTROL FROM PARENT PLACEHOLDER
           Me.Dispose()

      Catch ex As Exception
           Common.SendError(ex.Message, "AttributeControl.btnAddAttribute_Click")
      End Try
 End Sub

 Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
      'WEB TAB
      getAttributes()
 End Sub

     Protected Sub getAttributes()
      Try
           Dim attr As String = ""
           Dim attrName As String = ""
           Dim attrValue As String = ""

           Dim ds As DataSet = getSQLData("SELECT VariantMapping FROM OD_Product_Data WHERE SKU='" & selectedSKU & "'")
           For Each dr As DataRow In ds.Tables(0).Rows()
                attr = dr(0).ToString
           Next
           ds = Nothing
           Dim attrArr As Array = attr.Split("|")
           For Each item As String In attrArr
                Dim attrDetail As Array = item.Split(":")
                attrName = attrDetail(0)
                attrValue = attrDetail(1)
                Dim ctrlAttributes As AttributeControl = LoadControl("ctrlAttribute.ascx")
                ctrlAttributes.AttributeName = attrName
                ctrlAttributes.AttributeValue = attrValue
                ctrlAttributes.ID = "ctrlAttribute-" & attrName
                phAttributes.Controls.Add(ctrlAttributes)
           Next
      Catch ex As Exception
           SendError(ex.Message, "Default.getAttributes")
      End Try
 End Sub

 Protected Sub btnAddAttribute_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddAttribute.Click
      Dim ctrlAttributes As AttributeControl = LoadControl("ctrlAttribute.ascx")
      ctrlAttributes.ID = "ctrlAttribute" & phAttributes.Controls.Count + 1
      phAttributes.Controls.Add(ctrlAttributes)
 End Sub

 Protected Sub btnCreateAttribute_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCreateAttribute.Click
      Dim ctrlAddAttribute As AddAttributeControl = LoadControl("ctrlAddAttribute.ascx")
      ctrlAddAttribute.SelectedSKU = selectedSKU
      ctrlAddAttribute.ID = "ctrlAddAttribute" & phAttributes.Controls.Count + 1
      phAttributes.Controls.Add(ctrlAddAttribute)
 End Sub