Page Tracing

 Enabling Tracing

<%@ Page Trace="true" ... %>

or 

protected void Page_Load(Object sender, EventArgs e)
{
    Trace.IsEnabled = true;
}

By default, trace messages are listed in the order they were written by your code. Alternatively, you 

can specify that messages should be sorted by  category using the TraceMode attribute in the  

Page directive: 

<%@ Page Trace="true" TraceMode="SortByCategory" %> 

or the TraceMode property of the Trace object in your code: 

Trace.TraceMode = TraceMode.SortByCategory;

 

Writing Trace Information

protected void cmdWrite_Click(Object sender, EventArgs e) 
{ 
    Trace.Write("About to place an item in session state."); 
    Session["Test"] = "Contents"; 
    Trace.Write("Placed item in session state."); 
}

or uses overloaded method:

protected void cmdWriteCategory_Click(Object sender, EventArgs e)
{
  Trace.Write("cmdWriteCategory_Click",
    "About to place an item in session state.");
  Session["Test"] = "Contents";
  Trace.Write("cmdWriteCategory_Click",
    "Placed item in session state.");
}

 

Trace an exception

protected void cmdError_Click(Object sender, EventArgs e) 
{ 
    try 
    { 
        DivideNumbers(5, 0); 
    } 
    catch (Exception err) 
    { 
        Trace.Warn("cmdError_Click", "Caught Error", err); 
    } 
} 
 
private decimal DivideNumbers(decimal number, decimal divisor) 
{ 
    return number/divisor; 
}

 

Application-Level Tracing

To enable application-level tracing, you need to  modify settings in the web.config file, as  

shown here: 

<configuration> 
  <system.web> 
    <trace enabled="true" requestLimit="10" pageOutput="false" /> 
    ... 
  </system.web> 
</configuration> 

To view tracing information, you request the trace.axd file in the web application’s root directory. This file doesn’t actually exist; instead, ASP.NET automa tically intercepts the request and interprets it as a request for the tracing information.  It will then list the most recent co llected requests, provided you’re making the request from the local machine or have enabled remote tracing