HtmlInputCheckBox.OnServerChange(EventArgs) Method
Definition
Important
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Raises the ServerChange event. 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 -> unitProtected Overridable Sub OnServerChange (e As EventArgs)Parameters
Examples
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)
{
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>
Remarks
This event is raised when the Web page is submitted to the server and the HtmlInputCheckBox control changes state from the previous post. This method allows you to override the base implementation and provide a custom handler for the event.
Note
The control must have view state enabled for the ServerChange event to work correctly.
Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.
The OnServerChange method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.
Notes to Inheritors
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.
