CheckBoxField 构造函数
定义
重要
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初始化 CheckBoxField 类的新实例。
public:
CheckBoxField();public CheckBoxField ();Public Sub New ()示例
下面的代码示例演示如何使用构造函数动态向控件添加 CheckBoxField 对象 GridView 。
<%@ 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)
{
// The columns need to be created only the first time
// the page is loaded.
if(!IsPostBack)
{
// Dynamically create columns to display the desired
// fields from the data source. Columns that are
// dynamically added to the GridView control are not persisted
// across posts and must be recreated each time the page is
// loaded.
// Create a BoundField object to display an author's last name.
BoundField lastNameBoundField = new BoundField();
lastNameBoundField.DataField = "au_lname";
lastNameBoundField.HeaderText = "Last Name";
// Create a CheckBoxField object to indicate whether the author
// is on contract.
CheckBoxField contractCheckBoxField = new CheckBoxField();
contractCheckBoxField.DataField = "contract";
contractCheckBoxField.HeaderText = "Contract";
// Add the columns to the Columns collection of the
// GridView control.
AuthorsGridView.Columns.Add(lastNameBoundField);
AuthorsGridView.Columns.Add(contractCheckBoxField);
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>CheckBoxField Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>CheckBoxField Constructor Example</h3>
<asp:gridview id="AuthorsGridView"
datasourceid="AuthorsSqlDataSource"
autogeneratecolumns="False"
runat="server">
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Pubs sample database. -->
<asp:sqldatasource id="AuthorsSqlDataSource"
selectcommand="SELECT [au_lname], [au_fname], [address], [city], [state], [zip], [contract] FROM [authors]"
connectionstring="server=localhost;database=pubs;integrated security=SSPI"
runat="server">
</asp:sqldatasource>
</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 Page_Load(sender as Object, e As EventArgs)
' The columns need to be created only the first time
' the page is loaded.
If Not IsPostBack Then
' Dynamically create columns to display the desired
' fields from the data source. Columns that are
' dynamically added to the GridView control are not persisted
' across posts and must be recreated each time the page is
' loaded.
' Create a BoundField object to display an author's last name.
Dim lastNameBoundField As BoundField = New BoundField
lastNameBoundField.DataField = "au_lname"
lastNameBoundField.HeaderText = "Last Name"
' Create a CheckBoxField object to indicate whether the author
' is on contract.
Dim contractCheckBoxField As CheckBoxField = New CheckBoxField
contractCheckBoxField.DataField = "contract"
contractCheckBoxField.HeaderText = "Contract"
' Add the columns to the Columns collection of the
' GridView control.
AuthorsGridView.Columns.Add(lastNameBoundField)
AuthorsGridView.Columns.Add(contractCheckBoxField)
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>CheckBoxField Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>CheckBoxField Constructor Example</h3>
<asp:gridview id="AuthorsGridView"
datasourceid="AuthorsSqlDataSource"
autogeneratecolumns="False"
runat="server">
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Pubs sample database. -->
<asp:sqldatasource id="AuthorsSqlDataSource"
selectcommand="SELECT [au_lname], [au_fname], [address], [city], [state], [zip], [contract] FROM [authors]"
connectionstring="server=localhost;database=pubs;integrated security=SSPI"
runat="server">
</asp:sqldatasource>
</form>
</body>
</html>
注解
使用此构造函数初始化类的新实例 CheckBoxField 。 将字段添加到动态创建的数据绑定控件时，通常使用此构造函数。
若要将对象动态添加到 CheckBoxField 数据绑定控件，请创建新 CheckBoxField 对象，设置其属性，然后将其添加到数据绑定控件的字段集合。 例如，如果使用控件 GridView ，请将 CheckBoxField 对象添加到 Columns 集合。
备注
尽管可以动态向数据绑定控件添加字段，但强烈建议将所有字段静态声明，然后根据需要显示或隐藏。 静态声明所有字段可减小父数据绑定控件的视图状态大小。