VB.NET CheckBoxList的兩倍。爲什麼？

Question

我每次點擊刪除按鈕，複選標記一倍數量：

Public Class About 
Inherits System.Web.UI.Page 

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 

    Dim di As New IO.DirectoryInfo("C:\Images\") 
    Dim imageArray As IO.FileInfo() = di.GetFiles() 
    Dim image As IO.FileInfo 

    'clear imageArray 


    'list the names of all images in the specified directory 
    For Each image In imageArray 
     CheckBoxList1.Items.Add(image.Name) 
    Next 

End Sub 

Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnDelete.Click 

    For count As Integer = 0 To CheckBoxList1.Items.Count - 1 
     If CheckBoxList1.Items(count).Selected Then 
      File.Delete("C:\Images\" & CheckBoxList1.Items(count).ToString) 
     End If 
    Next 

End Sub 

末級

的CheckBoxList的不刷新，使得我刪除的複選框從CheckBoxList的去除。我如何實現這一目標？謝謝！

Answer 1

點擊一個按鈕，Page_Load中再次跑了，所以，增加了複選框的代碼跑第二次。

添加對Page.IsPostBack的檢查，並且只添加複選框，如果它不是回發。

If Not Page.IsPostBack Then 
    For Each image In imageArray 
     CheckBoxList1.Items.Add(image.Name) 
    Next 
End If 

（我希望的語法是正確的......不是用來VB）

Answer 2

Page_Load事件處理程序的全部內容，必須在你的情況下，只執行一次，所以把它改寫這樣的：

If Not IsPostBack Then 

    Dim di As New IO.DirectoryInfo("C:\Images\") 
    Dim imageArray As IO.FileInfo() = di.GetFiles() 
    Dim image As IO.FileInfo 

    'clear imageArray 


    'list the names of all images in the specified directory 
    For Each image In imageArray 
     CheckBoxList1.Items.Add(image.Name) 
    Next 

End If