TraceContext.Warn Method

public:
 void Warn(System::String ^ message);

public void Warn (string message);

member this.Warn : string -> unit

Public Sub Warn (message As String)

Parameters

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

• ASP.NET Tracing Overview

public:
 void Warn(System::String ^ category, System::String ^ message);

public void Warn (string category, string message);

member this.Warn : string * string -> unit

Public Sub Warn (category As String, message As String)

Parameters

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

• ASP.NET Tracing Overview

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 -> unit

Public Sub Warn (category As String, message As String, errorInfo As Exception)

Parameters

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.

See also

• Exception
• ASP.NET Tracing Overview