HtmlInputCheckBox.OnServerChange(EventArgs) 方法
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
引發 ServerChange 事件。 這個方法允許您直接處理事件。
protected:
virtual void OnServerChange(EventArgs ^ e);
protected virtual void OnServerChange (EventArgs e);
abstract member OnServerChange : EventArgs -> unit
override this.OnServerChange : EventArgs -> unit
Protected Overridable Sub OnServerChange (e As EventArgs)
參數
範例
下列程式碼範例示範如何指定 和 撰寫 ServerChange 事件的處理常式程式碼。
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>HtmlInputCheckBox Sample</title>
<script language="C#" runat="server">
void Button1_Click(object sender, EventArgs e)
{
if (Prev_Check_State.Value == Check1.Checked.ToString())
Span2.InnerHtml = "CheckBox1 did not change state between clicks.";
if (Check1.Checked)
{
Span1.InnerHtml = "CheckBox1 is selected!";
Prev_Check_State.Value="True";
}
else
{
Span1.InnerHtml = "CheckBox1 is not selected!";
Prev_Check_State.Value="False";
}
}
void Server_Changed(object sender, EventArgs e)
{
Span2.InnerHtml = "CheckBox1 changed state between clicks.";
}
</script>
</head>
<body>
<h3>HtmlInputCheckBox Sample</h3>
<form id="form1" runat="server">
<input id="Check1"
type="checkbox"
onserverchange="Server_Changed"
runat="server"/>
CheckBox1
<span id="Span1"
style="color:red"
runat="server"/>
<br />
<input type="button"
id="Button1"
value="Enter"
onserverclick="Button1_Click"
runat="server"/>
<br /><br />
<span id="Span2"
runat="server"/>
<input type="hidden" id="Prev_Check_State"
visible="false"
runat="server"/>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>HtmlInputCheckBox Sample</title>
<script language="VB" runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
If Prev_Check_State.Value = Check1.Checked.ToString() Then
Span2.InnerHtml = "CheckBox1 did not change state between clicks."
End If
If Check1.Checked = True Then
Span1.InnerHtml = "CheckBox1 is selected!"
Prev_Check_State.Value = "True"
Else
Span1.InnerHtml = "CheckBox1 is not selected!"
Prev_Check_State.Value = "False"
End If
End Sub 'Button1_Click
Sub Server_Changed(sender As Object, e As EventArgs)
Span2.InnerHtml = "CheckBox1 changed state between clicks."
End Sub 'Server_Changed
</script>
</head>
<body>
<h3>HtmlInputCheckBox Sample</h3>
<form id="form1" runat="server">
<input id="Check1"
type="checkbox"
onserverchange="Server_Changed"
runat="server"/>
CheckBox1
<span id="Span1"
style="color:red"
runat="server"/>
<br />
<input type="button"
id="Button1"
value="Enter"
onserverclick="Button1_Click"
runat="server"/>
<br /><br />
<span id="Span2"
runat="server"/>
<input type="hidden" id="Prev_Check_State"
visible="false"
runat="server"/>
</form>
</body>
</html>
備註
當網頁提交至伺服器,且 HtmlInputCheckBox 控制項會變更先前文章的狀態時,就會引發此事件。 此方法可讓您覆寫基底實作,並提供事件的自訂處理常式。
注意
控制項必須啟用檢視狀態, ServerChange 事件才能正常運作。
引發事件會透過委派叫用此事件處理常式。 如需詳細資訊,請參閱 處理和引發事件。
OnServerChange 方法也允許衍生類別處理事件,而不用附加委派。 這是在衍生類別中處理事件的慣用技巧。
給繼承者的注意事項
當在衍生類別中覆寫 OnServerChange(EventArgs) 時,請確定呼叫基底類別的 OnServerChange(EventArgs) 方法,使已註冊的委派能接收到事件。