TraceContext.Warn Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Writes trace information to the trace log. Unlike Write(String), all warnings appear in the log as red text.
Overloads
| Warn(String) |
Writes a trace message to the trace log. All warnings appear in the log as red text. |
| Warn(String, String) |
Writes trace information to the trace log, including any user-defined categories and trace messages. All warnings appear in the log as red text. |
| Warn(String, String, Exception) |
Writes trace information to the trace log, including any user-defined categories, trace messages, and error information. All warnings appear in the log as red text. |
Warn(String)
Writes a trace message to the trace log. All warnings appear in the log as red text.
public:
void Warn(System::String ^ message);public void Warn (string message);member this.Warn : string -> unitPublic Sub Warn (message As String)Parameters
- message
- String
The trace message to write to the log.
Remarks
Every time the Warn method is called, a TraceContext trace message is added to the TraceRecords messages collection, which is accessible when you handle the TraceFinished event. The message is added with its IsWarning property set to true and its ErrorInfo property set to null.
See also
Applies to
Warn(String, String)
Writes trace information to the trace log, including any user-defined categories and trace messages. All warnings appear in the log as red text.
public:
void Warn(System::String ^ category, System::String ^ message);public void Warn (string category, string message);member this.Warn : string * string -> unitPublic Sub Warn (category As String, message As String)Parameters
- category
- String
The trace category that receives the message.
- message
- String
The trace message to write to the log.
Remarks
Every time the Warn method is called, a TraceContext trace message is added to the TraceRecords messages collection, which is accessible when you handle the TraceFinished event. The message is added with its IsWarning property set to true and its ErrorInfo property set to null.
See also
Applies to
Warn(String, String, Exception)
Writes trace information to the trace log, including any user-defined categories, trace messages, and error information. All warnings appear in the log as red text.
public:
void Warn(System::String ^ category, System::String ^ message, Exception ^ errorInfo);public void Warn (string category, string message, Exception errorInfo);member this.Warn : string * string * Exception -> unitPublic Sub Warn (category As String, message As String, errorInfo As Exception)Parameters
- category
- String
The trace category that receives the message.
- message
- String
The trace message to write to the log.
Examples
The following code example demonstrates how to call the Write method to write an error trace message to the trace log. In this example, different exceptions are traced as errors and warnings. When the page throws an ArgumentException, it writes a warning message using the Warn method. When the page throws an InvalidOperationException, it writes an error message using the Write method.
<%@ 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);
try {
throw new ArgumentException("Trace Test");
}
catch (InvalidOperationException ioe) {
// You can write an error trace message using the Write method.
Trace.Write("Exception Handling", "Exception: Page_Load.", ioe);
}
catch (ArgumentException ae) {
// You can write a warning trace message using the Warn method.
Trace.Warn("Exception Handling", "Warning: Page_Load.", ae);
}
}
// 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;
if (r.IsWarning) {
Response.Write(String.Format("warning message: {0} <BR>", r.Message));
}
else {
Response.Write(String.Format("error 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
Try
Dim ae As New ArgumentException("Trace Test")
Throw ae
catch ioe As InvalidOperationException
' You can write an error trace message using the Write method.
Trace.Write("Exception Handling", "Exception: Page_Load.", ioe)
Catch ae As ArgumentException
' You can write a warning trace message using the Warn method.
Trace.Warn("Exception Handling", "Warning: Page_Load.", ae)
End Try
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)
If r.IsWarning Then
Response.Write(String.Format("warning message: {0} <BR>", r.Message))
Else
Response.Write(String.Format("error message: {0} <BR>", r.Message))
End If
Next
End Sub ' OnTraceFinished
</script>
Remarks
Every time the Warn method is called, a TraceContext trace message is added to the TraceRecords messages collection, which is accessible when you handle the TraceFinished event. The message is added with its IsWarning property set to true, and the ErrorInfo property is set to the object passed by the errorInfo parameter.
