.NET Framework 类库
Control.OnLoad 方法

引发 Load 事件。

命名空间:System.Web.UI
程序集:System.Web（在 system.web.dll 中）

语法
Visual Basic（声明） 
Protected Friend Overridable Sub OnLoad ( _
    e As EventArgs _
)
Visual Basic（用法） 
Dim e As EventArgs

Me.OnLoad(e)
C# 
protected internal virtual void OnLoad (
    EventArgs e
)
C++ 
protected public:
virtual void OnLoad (
    EventArgs^ e
)
J# 
protected void OnLoad (
    EventArgs e
)
JScript 
protected internal function OnLoad (
    e : EventArgs
)

参数

e

包含事件数据的 EventArgs 对象。

备注

此方法通知服务器控件应执行关联页的每个 HTTP 请求的共同操作，例如设置数据库查询。在页生存期的此阶段，创建并初始化层次结构中的服务器控件，还原视图状态，并且窗体控件反映客户端数据。

使用 IsPostBack 属性确定该页是否正为响应客户端回发而加载，或者它是否正被首次加载和访问。
示例

下面的示例创建一个文本流对象 myFile；如果在处理请求期间发生定义的 Page 和控件生命周期事件，则使用该对象将消息输出到文本文件。在调用 OnLoad 方法期间，字符串 "Custom control has loaded" 将写入文件，并文本流对象将关闭。

Visual Basic 
' Create a StreamWriter to write data to a text file.
 Dim myFile As TextWriter = File.CreateText("c:\NewTextFile.txt")

Sub Page_Load(sender As Object, e As EventArgs)
   ' Write status to file.
   myFile.WriteLine("Page has loaded.")
End Sub

Sub CustomControl_OnLoad(sender As Object, e As EventArgs)
   myFile.WriteLine("Custom control has loaded.")
End Sub

Sub CustomControl_OnUnload(sender As Object, e As EventArgs)
   ' Server controls final cleanup such as;
   ' closing files etc.goes here         
   myFile.WriteLine("Custom control was unloaded.")
   ' Close the stream object.
   myFile.Close()
End Sub
C# 
// Create a StreamWriter to write data to a text file.
TextWriter myFile = File.CreateText("c:\\NewTextFile.txt");

void Page_Load(object sender,EventArgs e)
{
   // Write status to file.
   myFile.WriteLine("Page has loaded.");
}
void CustomControl_OnLoad(object sender,EventArgs e)
{
   myFile.WriteLine("Custom control has loaded.");
}

void CustomControl_OnUnload(object sender,EventArgs e)
{
   // Server controls final cleanup such as; 
   // closing files goes here         
   myFile.WriteLine("Custom control was unloaded.");
  // Close the stream object.
   myFile.Close();
}
J# 
// Create a StreamWriter to write data to a text file.
TextWriter myFile = File.CreateText("c:\\NewTextFile.txt");

void Page_Load(Object sender,EventArgs e)
{
    // Write status to file.
    myFile.WriteLine("Page has loaded.");
} //Page_Load

void CustomControl_OnLoad(Object sender,EventArgs e)
{
    myFile.WriteLine("Custom control has loaded.");
} //CustomControl_OnLoad

void CustomControl_OnUnload(Object sender,EventArgs e)
{
    // Server controls final cleanup such as; 
    // closing files goes here         
    myFile.WriteLine("Custom control was unloaded.");
    // Close the stream object.
    myFile.Close();
} //CustomControl_OnUnload
平台

Windows 98、Windows 2000 SP4、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0
请参见
标记 :


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