CheckBoxList 构造函数
定义
重要
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初始化 CheckBoxList 类的新实例。
public:
CheckBoxList();public CheckBoxList ();Public Sub New ()示例
下面的代码示例演示如何创建和初始化 控件的新实例 CheckBoxList 。
注意
下面的代码示例使用单文件代码模型，如果直接复制到代码隐藏文件中，可能无法正常工作。 必须将此代码示例复制到扩展名为 .aspx 的空文本文件中。 有关 Web 窗体代码模型的详细信息，请参阅 ASP.NET Web 窗体页代码模型。
<%@ 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> CheckBoxList Constructor Example </title>
<script runat="server">
void Check_Clicked(Object sender, EventArgs e)
{
// Retrieve the CheckBoxList control from the Controls collection
// of the PlaceHolder control.
CheckBoxList checklist =
(CheckBoxList)Place.FindControl("checkboxlist1");
// Make sure a control was found.
if(checklist != null)
{
Message.Text = "Selected Item(s):<br /><br />";
// Iterate through the Items collection of the CheckBoxList
// control and display the selected items.
for (int i=0; i<checklist.Items.Count; i++)
{
if (checklist.Items[i].Selected)
{
Message.Text += checklist.Items[i].Text + "<br />";
}
}
}
else
{
// Display an error message.
Message.Text = "Unable to find CheckBoxList control.";
}
}
void Page_Load(Object sender, EventArgs e)
{
// Create a new CheckBoxList control.
CheckBoxList checklist = new CheckBoxList();
// Set the properties of the control.
checklist.ID = "checkboxlist1";
checklist.AutoPostBack = true;
checklist.CellPadding = 5;
checklist.CellSpacing = 5;
checklist.RepeatColumns = 2;
checklist.RepeatDirection = RepeatDirection.Vertical;
checklist.RepeatLayout = RepeatLayout.Flow;
checklist.TextAlign = TextAlign.Right;
// Populate the CheckBoxList control.
checklist.Items.Add(new ListItem("Item 1"));
checklist.Items.Add(new ListItem("Item 2"));
checklist.Items.Add(new ListItem("Item 3"));
checklist.Items.Add(new ListItem("Item 4"));
checklist.Items.Add(new ListItem("Item 5"));
checklist.Items.Add(new ListItem("Item 6"));
// Manually register the event-handling method for the
// SelectedIndexChanged event.
checklist.SelectedIndexChanged += new EventHandler(this.Check_Clicked);
// Add the control to the Controls collection of the
// PlaceHolder control.
Place.Controls.Add(checklist);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3> CheckBoxList Constructor Example </h3>
Select items from the CheckBoxList.
<br /><br />
<asp:PlaceHolder id="Place" runat="server"/>
<br /><br />
<asp:label id="Message" 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 runat="server">
<title> CheckBoxList Constructor Example </title>
<script runat="server">
Sub Check_Clicked(sender As Object, e As EventArgs)
' Retrieve the CheckBoxList control from the Controls collection
' of the PlaceHolder control.
Dim checklist As CheckBoxList = _
CType(Place.FindControl("checkboxlist1"), CheckBoxList)
' Make sure a control was found.
If Not checklist Is Nothing
Message.Text = "Selected Item(s):<br /><br />"
' Iterate through the Items collection of CheckBoxList
' control and display the selected items.
Dim i As Integer
For i=0 To checklist.Items.Count - 1
If checklist.Items(i).Selected Then
Message.Text &= checklist.Items(i).Text & "<br />"
End If
Next i
Else
' Display an error message.
Message.Text = "Unable to find CheckBoxList control."
End If
End Sub
Sub Page_Load(sender As Object, e As EventArgs)
' Create a new CheckBoxList control.
Dim checklist As CheckBoxList = New CheckBoxList()
' Set the properties of the control.
checklist.ID = "checkboxlist1"
checklist.AutoPostBack = True
checklist.CellPadding = 5
checklist.CellSpacing = 5
checklist.RepeatColumns = 2
checklist.RepeatDirection = RepeatDirection.Vertical
checklist.RepeatLayout = RepeatLayout.Flow
checklist.TextAlign = TextAlign.Right
' Populate the CheckBoxList control.
checklist.Items.Add(New ListItem("Item 1"))
checklist.Items.Add(New ListItem("Item 2"))
checklist.Items.Add(New ListItem("Item 3"))
checklist.Items.Add(New ListItem("Item 4"))
checklist.Items.Add(New ListItem("Item 5"))
checklist.Items.Add(New ListItem("Item 6"))
' Manually register the event-handling method for the
' SelectedIndexChanged event.
AddHandler checklist.SelectedIndexChanged, AddressOf Check_Clicked
' Add the control to the Controls collection of the
' PlaceHolder control.
Place.Controls.Add(checklist)
End Sub
</script>
</head>
<body>
<form id="form1" runat="server">
<h3> CheckBoxList Constructor Example </h3>
Select items from the CheckBoxList.
<br /><br />
<asp:PlaceHolder id="Place" runat="server"/>
<br /><br />
<asp:label id="Message" runat="server"/>
</form>
</body>
</html>
注解
使用此构造函数创建和初始化 类的新实例 CheckBoxList 。
