TraceContextEventHandler 委托

定义

public delegate void TraceContextEventHandler(System::Object ^ sender, TraceContextEventArgs ^ e);

public delegate void TraceContextEventHandler(object sender, TraceContextEventArgs e);

type TraceContextEventHandler = delegate of obj * TraceContextEventArgs -> unit

Public Delegate Sub TraceContextEventHandler(sender As Object, e As TraceContextEventArgs)

参数

示例

下面的代码示例演示如何注册 TraceContextEventHandler 委托来处理 TraceFinished 事件。 在此示例中， OnTraceFinished 方法循环访问跟踪记录，并将其写入响应流。

<%@ Page language="c#" Trace="true" %>
<script runat="server">
void Page_Load(object sender, EventArgs e)
{
    // Register a handler for the TraceFinished event.
    Trace.TraceFinished += new 
        TraceContextEventHandler(this.OnTraceFinished);

    // Write a trace message.
    Trace.Write("Web Forms Infrastructure Methods", "USERMESSAGE: Page_Load complete.");
}
 
// A TraceContextEventHandler for the TraceFinished event.
void OnTraceFinished(object sender, TraceContextEventArgs e)
{
    TraceContextRecord r = null;    
    
    // Iterate through the collection of trace records and write 
    // them to the response stream.
    foreach(object o in e.TraceRecords)
    {
        r = (TraceContextRecord)o;
        Response.Write(String.Format("trace message: {0} <BR>", r.Message));
    }
}       
</script>

<%@ Page language="VB" Trace="true" %>
<script runat="server">
' The Page_Load method.
Private Sub Page_Load(sender As Object, e As EventArgs)

    ' Register a handler for the TraceFinished event.
    AddHandler Trace.TraceFinished, AddressOf OnTraceFinished

    ' Write a trace message.
    Trace.Write("Web Forms Infrastructure Methods", "USERMESSAGE: Page_Load complete.")
End Sub ' Page_Load
 
' A TraceContextEventHandler for the TraceFinished event.
Private Sub OnTraceFinished(sender As Object, e As TraceContextEventArgs)

    Dim r As TraceContextRecord
    Dim o As Object
    
    ' Iterate through the collection of trace records and write 
    ' them to the response stream.

    For Each o In e.TraceRecords
        r = CType(o, TraceContextRecord)
        Response.Write(String.Format("trace message: {0} <BR>", r.Message))
    Next

End Sub ' OnTraceFinished
</script>

注解

创建 TraceContextEventHandler 委托时，需要标识将处理该事件的方法。 若要将事件与事件处理程序关联，请将该委托的一个实例添加到事件中。 除非移除了该委托，否则每当发生该事件时就会调用事件处理程序。

有关事件处理程序委托的详细信息，请参阅 处理和引发事件。

另请参阅

• TraceContextEventArgs
• TraceFinished
• TraceContext
• ASP.NET 跟踪概述