HtmlInputCheckBox.OnServerChange(EventArgs) Método
Definição
Aciona o evento ServerChange.Raises the ServerChange event. Este método permite a você manipular o evento diretamente.This method allows you to handle the event directly.
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)
Parâmetros
Exemplos
O exemplo de código a seguir demonstra como especificar e codificar um manipulador para o ServerChange evento.The following code example demonstrates how to specify and code a handler for the ServerChange event.
<%@ 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 == true)
{
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>
Comentários
Esse evento é gerado quando a página da Web é enviada para o servidor e o HtmlInputCheckBox estado do controle é alterado da postagem anterior.This event is raised when the Web page is submitted to the server and the HtmlInputCheckBox control changes state from the previous post. Esse método permite que você substitua a implementação base e forneça um manipulador personalizado para o evento.This method allows you to override the base implementation and provide a custom handler for the event.
Observação
O controle deve ter o estado de exibição habilitado para que o ServerChange evento funcione corretamente.The control must have view state enabled for the ServerChange event to work correctly.
A geração de um evento invoca o manipulador de eventos por meio de um delegado.Raising an event invokes the event handler through a delegate. Para obter mais informações, consulte manipulando e gerando eventos.For more information, see Handling and Raising Events.
O OnServerChange método também permite que classes derivadas manipulem o evento sem anexar um delegado.The OnServerChange method also allows derived classes to handle the event without attaching a delegate. Essa é a técnica preferida para manipular o evento em uma classe derivada.This is the preferred technique for handling the event in a derived class.
Notas aos Herdeiros
Ao substituir OnServerChange(EventArgs) em uma classe derivada, certifique-se de chamar o método da classe base OnServerChange(EventArgs) para que os delegados registrados recebam o evento.When overriding OnServerChange(EventArgs) in a derived class, be sure to call the base class's OnServerChange(EventArgs) method so that registered delegates receive the event.