CheckBox.AutoPostBack Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets a value indicating whether the CheckBox state automatically posts back to the server when clicked.
public:
virtual property bool AutoPostBack { bool get(); void set(bool value); };public virtual bool AutoPostBack { get; set; }[System.Web.UI.Themeable(false)]
public virtual bool AutoPostBack { get; set; }member this.AutoPostBack : bool with get, set[<System.Web.UI.Themeable(false)>]
member this.AutoPostBack : bool with get, setPublic Overridable Property AutoPostBack As BooleanProperty Value
true to automatically post the state of the CheckBox control to the server when it is clicked; otherwise, false. The default is false.
- Attributes
Examples
The following example demonstrates how to use the AutoPostBack property to automatically post the state of the CheckBox control to the server when the control is clicked.
Note
The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. This code sample must be copied into an empty text file that has an .aspx extension. For more information on the Web Forms code model, see ASP.NET Web Forms Page Code Model.
<%@ 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 runat="server">
<title>CheckBox CheckedChanged Example</title>
<script runat="server">
void Check_Clicked(Object sender, EventArgs e)
{
// Calculate the subtotal and display the result in currency format.
// Include tax if the check box is selected.
Message.Text = CalculateTotal(checkbox1.Checked).ToString("c");
}
void Page_Load(Object sender, EventArgs e)
{
// Display the subtotal without tax when the page is first loaded.
if(!IsPostBack)
{
// Calculate the subtotal and display the result in currency format.
Message.Text = CalculateTotal(false).ToString("c");
}
}
double CalculateTotal(bool Taxable)
{
// Calculate the subtotal for the example.
double Result = 1.99 + 2.99 + 3.99;
// Add tax, if applicable.
if(Taxable)
{
Result += Result * 0.086;
}
return Result;
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>CheckBox CheckedChanged Example</h3>
Select whether to include tax in the subtotal.
<br /><br />
<table border="1" cellpadding="5">
<tr>
<th colspan="2">
Shopping cart
</th>
</tr>
<tr>
<td>
Item 1
</td>
<td>
$1.99
</td>
</tr>
<tr>
<td>
Item 2
</td>
<td>
$2.99
</td>
</tr>
<tr>
<td>
Item 3
</td>
<td>
$3.99
</td>
</tr>
<tr>
<td>
<b>Subtotal</b>
</td>
<td>
<asp:Label id="Message" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:CheckBox id="checkbox1" runat="server"
AutoPostBack="True"
Text="Include 8.6% sales tax"
TextAlign="Right"
OnCheckedChanged="Check_Clicked"/>
</td>
</tr>
</table>
</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 runat="server">
<title>CheckBox CheckedChanged Example</title>
<script runat="server">
Sub Check_Clicked(sender As Object, e As EventArgs)
' Calculate the subtotal and display the result in currency format.
' Include tax if the check box is selected.
Message.Text = CalculateTotal(checkbox1.Checked).ToString("c")
End Sub
Sub Page_Load(sender As Object, e As EventArgs)
' Display the subtotal without tax when the page is first loaded.
If Not IsPostBack Then
' Calculate the subtotal and display the result in currency format.
Message.Text = CalculateTotal(false).ToString("c")
End If
End Sub
Function CalculateTotal(Taxable As Boolean) As Double
' Calculate the subtotal for the example.
Dim Result As Double = 1.99 + 2.99 + 3.99
' Add tax, if applicable.
If(Taxable)
Result += Result * 0.086
End If
Return Result
End Function
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>CheckBox CheckedChanged Example</h3>
Select whether to include tax in the subtotal.
<br /><br />
<table border="1" cellpadding="5">
<tr>
<th colspan="2">
Shopping cart
</th>
</tr>
<tr>
<td>
Item 1
</td>
<td>
$1.99
</td>
</tr>
<tr>
<td>
Item 2
</td>
<td>
$2.99
</td>
</tr>
<tr>
<td>
Item 3
</td>
<td>
$3.99
</td>
</tr>
<tr>
<td>
<b>Subtotal</b>
</td>
<td>
<asp:Label id="Message" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:CheckBox id="checkbox1" runat="server"
AutoPostBack="True"
Text="Include 8.6% sales tax"
TextAlign="Right"
OnCheckedChanged="Check_Clicked"/>
</td>
</tr>
</table>
</form>
</body>
</html>
Remarks
Use this property to specify whether the state of the CheckBox control is posted back to the server when clicked.
Note
Setting this property to true causes a round trip to the server every time the control is clicked.
This property cannot be set by themes or style sheet themes. For more information, see ThemeableAttribute and ASP.NET Themes and Skins.
