VB.net - 使數據庫中的Gridview複選框更新布爾字段

Question

有很多關於這個問題，但我一直無法解決我的問題，使用任何人的答案（經過許多次嘗試..）

我正在vb.net中創建一個asp.net web應用程序。我有一個SqlDataSource和我的網頁上一個GridView：

<asp:SqlDataSource ID="msgUnread" runat="server" 
ConnectionString="<%$ ConnectionStrings:edinsec %>" 

SelectCommand="SELECT [msgdate], [email], [name], [message], [readit] FROM [messages]" 
UpdateCommand="UPDATE messages SET readit = 'True' WHERE (msgid = @msgid)"> 
     <UpdateParameters> 
    <asp:Parameter Name="msgid" /> 
</UpdateParameters> 
    </asp:SqlDataSource> 


    <asp:GridView ID="unreadMessages" runat="server" AutoGenerateColumns="False" 
BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" 
CellPadding="3" DataSourceID="msgUnread"> 
<RowStyle ForeColor="#000066" /> 
<Columns> 
    <asp:BoundField DataField="msgdate" HeaderText="Date &amp; time" 
     SortExpression="msgdate" /> 
    <asp:BoundField DataField="email" HeaderText="Email" 
     SortExpression="email" /> 
    <asp:BoundField DataField="name" HeaderText="Name" SortExpression="name" /> 
       <asp:TemplateField HeaderText="Mark as read" SortExpression="readit"> 
     <%--<EditItemTemplate> 
      <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Bind("readit") %>' OnCheckedChange="CheckBox1_CheckedChanged" /> 
     </EditItemTemplate>--%> 
     <ItemTemplate> 
      <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Bind("readit") %>' OnCheckChanged="CheckBox1_CheckedChanged" AutoPostBack="true"/> 
     </ItemTemplate> 
    </asp:TemplateField> 
</Columns> 
<FooterStyle BackColor="White" ForeColor="#000066" /> 
<PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" /> 
<SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" /> 
<HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" /> 
    </asp:GridView> 

GridView控件填充正確，與複選框被正確顯示的值（即‘readit’字段是位字段，即布爾）。我試圖讓該腳本在單擊複選框時更新數據庫中的布爾值。目前，儘管我甚至無法讓腳本對點擊作出反應（甚至沒有MsgBox）。

這裏是我隱藏：

Public Partial Class enqur 
Inherits System.Web.UI.Page 
WithEvents CheckBox1 As CheckBox 


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

End Sub 

Public Sub CheckBox1_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) 
    MsgBox("test") 
End Sub 

End Class 

正如你可以看到我用WITHEVENTS玩，但似乎並沒有幫助。在上面的代碼中，我試圖得到的是點擊複選框的某種反應 - 但沒有任何反應（也沒有錯誤）。

我很難過。誰能幫忙？將不勝感激:)

Answer 1

經過一番faffing約我結束了這段代碼在aspx文件：

<asp:TemplateField HeaderText="readit" SortExpression="readit"> 
    <ItemTemplate> 
     <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="true" OnCheckedChanged="checkbox_CheckedChanged" Checked='<%# Bind("readit") %>' 
      Enabled="true" /> 
    </ItemTemplate> 
    <EditItemTemplate> 
     <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="true" OnCheckedChanged="checkbox_CheckedChanged" Checked='<%# Bind("readit") %>' /> 
    </EditItemTemplate> 
     </asp:TemplateField> 

...這在代碼隱藏：

Public Sub checkbox_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) 'Handles checkbox.CheckedChanged 
    Dim box As CheckBox = DirectCast(sender, CheckBox) 



    If box.Checked = True Then 
    MsgBox("checked!") 
    Else 
    MsgBox("unchecked!") 
    End If 



End Sub 

...這觸發正確的點擊每個複選框。現在讓他們做一些有用的事情...

Answer 2

變化

Public Sub CheckBox1_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) 

到

Public Sub CheckBox1_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) Handles CheckBox1.CheckedChange 

基本上你忘了把手CheckBox1.CheckedChange底。

Answer 3

錯誤：當我在代碼後面的代碼段中添加「Handles CheckBox1.CheckedChanged」時，CheckBox1被加下劃線，並且出現以下錯誤：「句柄子句需要一個WithEvents變量，含有類型或其基本類型之一「。我該如何擺脫？我剛剛刪除了該行並在沒有它的情況下運行了代碼。

要更改由Gridview複選框表示的DoNotMail布爾值並在數據庫中自動更新（如果複選框從0（False，Will Mail）複選到1（True，Will Mail），這裏是我使用的代碼。

因爲我背後的default.aspx.vb碼補充說：

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
    lastname.Focus() //sets the focus on the last name text box 
    If Page.IsPostBack Then 
     Response.Write("The DoNotMail value has been changed in the database for the selected field") 
    End If 

End Sub 

Public Sub checkbox1_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) 
    Dim box As CheckBox = DirectCast(sender, CheckBox) 
    If box.Checked = True Then 
     donotmail.SelectedValue = 1 
    Else 
     donotmail.SelectedValue = 0 
    End If 


End Sub 

對於Default.aspx頁，我添加：

    <asp:TemplateField HeaderText="DoNotMail" SortExpression="DoNotMail">  
       <ItemTemplate>   
       <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="true" OnCheckedChanged="checkbox1_CheckedChanged" Checked='<%# Bind("DoNotMail") %>' 
           Enabled="true" />  
       </ItemTemplate>  
       <EditItemTemplate>   
       <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="true" OnCheckedChanged="checkbox1_CheckedChanged" Checked='<%# Bind("DoNotMail") %>' />  
       </EditItemTemplate>  
       </asp:TemplateField>