PersistChildrenAttribute.IsDefaultAttribute 方法
定义
重要
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返回一个值，该值指示类的当前实例 PersistChildrenAttribute 的值是否为派生类的默认值。
public:
override bool IsDefaultAttribute();public override bool IsDefaultAttribute();override this.IsDefaultAttribute : unit -> boolPublic Overrides Function IsDefaultAttribute () As Boolean返回
true 如果当前实例的值为默认实例 PersistChildrenAttribute ，则为 ;否则为 false。
示例
下面的代码示例演示如何使用 IsDefaultAttribute 该方法来确定类的 PersistChildrenAttribute 当前实例是否与默认实例相同。
该代码示例是 PersistChildrenAttribute 类中的一个较大示例的一部分。
<%@ Page Language="C#" %>
<%@ Register TagPrefix="AspSample" Assembly="Samples.AspNet.CS.Controls" Namespace="PersistChildrenSamples" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
// Create two new employees and add them to the custom control.
Employee e1 = new Employee("Employee 1", "Title 1", "Alias 1");
Employee e2 = new Employee("Employee 2", "Title 2", "Alias 2");
CollectionPropertyControl1.Employees.Add(e1);
CollectionPropertyControl1.Employees.Add(e2);
// Verify attribute values.
PersistChildrenAttribute p =
(PersistChildrenAttribute)Attribute.GetCustomAttribute(typeof(CollectionPropertyControl),
typeof(PersistChildrenAttribute));
StringBuilder sb = new StringBuilder();
sb.Append("The Persist property is " + p.Persist.ToString() + "<br />");
sb.Append("The UseCustomPersistence property is " + p.UsesCustomPersistence.ToString() + "<br />");
sb.Append("The IsDefault method returns " + p.IsDefaultAttribute().ToString());
Message.Text = sb.ToString();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>PersistChildrenAttribute</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Message"
runat="server"/>
<AspSample:CollectionPropertyControl id="CollectionPropertyControl1"
runat="server">
</AspSample:CollectionPropertyControl>
</div>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Register TagPrefix="AspSample" Assembly="Samples.AspNet.VB.Controls" Namespace="PersistChildrenSampleVB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
' Create two new employees and add them to the custom control.
Dim e1 As New Employee("Employee 1", "Title 1", "Alias 1")
Dim e2 As New Employee("Employee 2", "Title 2", "Alias 2")
CollectionPropertyControl1.Employees.Add(e1)
CollectionPropertyControl1.Employees.Add(e2)
' Verify attribute values.
Dim p As PersistChildrenAttribute = _
Attribute.GetCustomAttribute(GetType(CollectionPropertyControl), _
GetType(PersistChildrenAttribute))
Dim sb As New StringBuilder()
sb.Append("The Persist property is " & p.Persist.ToString() & "<br />")
sb.Append("The UseCustomPersistence property is " & p.UsesCustomPersistence.ToString() & "<br />")
sb.Append("The IsDefault method returns " & p.IsDefaultAttribute().ToString())
Message.Text = sb.ToString()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>PersistChildrenAttribute</title>
</head>
<body>
<form id="Form1" runat="server">
<div>
<asp:Label ID="Message"
runat="server"/>
<AspSample:CollectionPropertyControl id="CollectionPropertyControl1"
runat="server">
</AspSample:CollectionPropertyControl>
</div>
</form>
</body>
</html>
