共用方式為


Button.OnClick(EventArgs) 方法

定義

引發 Click 控制項的 Button 事件。

protected:
 virtual void OnClick(EventArgs ^ e);
protected virtual void OnClick (EventArgs e);
abstract member OnClick : EventArgs -> unit
override this.OnClick : EventArgs -> unit
Protected Overridable Sub OnClick (e As EventArgs)

參數

e
EventArgs

事件資料。

範例

下列程式代碼範例示範如何指定和撰寫事件的事件處理程式 Click 程式代碼,以在網頁上顯示簡單的訊息。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    
    void Page_Load(Object sender, EventArgs e)
    {
        // Manually register the event-handling method for
        // the Click event of the Button control.
        Button1.Click += new EventHandler(this.GreetingBtn_Click);
    }

    void GreetingBtn_Click(Object sender,
                           EventArgs e)
    {
        // When the button is clicked,
        // change the button text, and disable it.

        Button clickedButton = (Button)sender;
        clickedButton.Text = "...button clicked...";
        clickedButton.Enabled = false;
        
        // Display the greeting label text.
        GreetingLabel.Visible = true;
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <h3>Simple Button Example</h3>
     
      <asp:Button id="Button1"
           Text="Click here for greeting..."
           OnClick="GreetingBtn_Click" 
           runat="server"/>
      <br />
      <br />
      <asp:Label ID="GreetingLabel" runat="server" 
                 Visible="false" Text="Hello World!" />
    </div>
    </form>
</body>
</html>
<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    
    Sub GreetingBtn_Click(ByVal sender As Object, _
                          ByVal e As EventArgs)
   
        ' When the button is clicked,
        ' change the button text, and disable it.
        
        Dim clickedButton As Button = sender
        clickedButton.Text = "...button clicked..."
        clickedButton.Enabled = False
 
        ' Display the greeting label text.
        GreetingLabel.Visible = True
    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Button Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <h3>Simple Button Example</h3>
     
      <asp:Button id="Button1"
           Text="Click here for greeting..."
           OnClick="GreetingBtn_Click" 
           runat="server"/>
      <br />
      <br />
      <asp:Label ID="GreetingLabel" runat="server" 
                 Visible="false" Text="Hello World!" />
    </div>
    </form>
</body>
</html>

備註

Click按兩下控件時Button,就會引發事件。 例如,當沒有命令名稱與 Button 控件相關聯時,通常會使用這個事件 (,而 [提交] 按鈕) 。

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

OnClick 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 OnClick(EventArgs) 時,請確定呼叫基底類別的 OnClick(EventArgs) 方法,使已註冊的委派能接收到事件。

適用於

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