Trace.Write Method (String, String)

Writes a category name and a message to the trace listeners in the Listeners collection.

Namespace:  System.Diagnostics
Assembly:  System (in System.dll)

'Declaration
<ConditionalAttribute("TRACE")> _
Public Shared Sub Write ( _
	message As String, _
	category As String _
)

Parameters

message
Type: System.String

A message to write.

category
Type: System.String

A category name used to organize the output.

By default, the output is written to an instance of DefaultTraceListener.

The category parameter can be used to group output messages.

This method calls the Write method of the trace listener.

NoteNote

ASP.NET supplies tracing functionality tailored for Web pages. To write trace messages in ASP.NET pages, use the Page.Trace property.

By default, in code associated with an ASP.NET Web page, the statement Trace.Write("...") is a call to the Write method of the Page.Trace property. To use the System.Diagnostics.Trace class in Web pages, you must include the namespace, for example, System.Diagnostics.Trace.Write("...").

The following example creates a TraceSwitch named generalSwitch. This switch is set outside the code sample.

If the switch is set to the TraceLevel Verbose, the example outputs the first error message to the Listeners. For information on adding a listener to the Listeners collection, see the TraceListenerCollection class.

Then, if the TraceLevel is set to Error or higher, the example outputs the second error message on the same line as the first message. The second message is followed by a line terminator.

    ' Class-level declaration. 
    ' Create a TraceSwitch. 
    Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")

    Public Shared Sub MyErrorMethod(myObject As Object, category As String)
        ' Write the message if the TraceSwitch level is set to Verbose. 
        If generalSwitch.TraceVerbose Then
            Trace.Write(myObject.ToString() & _
                " is not a valid object for category: ", category)
        End If 

        ' Write a second message if the TraceSwitch level is set to Error or higher. 
        If generalSwitch.TraceError Then
            Trace.WriteLine(" Please use a different category.")
        End If 
    End Sub

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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