Windows 桌面应用程序

Cmdlet.WriteWarning Method

Writes a warning message that can be displayed.

Namespace: System.Management.Automation
Assembly: System.Management.Automation (in System.Management.Automation.dll)

Dim instance As Cmdlet
Dim text As String


public void WriteWarning (
	string text
public void WriteWarning (
	String text
public function WriteWarning (
	text : String



The warning message to be displayed.

Exception typeCondition

The pipeline is stopped. The pipeline was terminated either before the call was made or while the call was in progress. By default, the cmdlet should allow the caller of the processing record method to catch this exception.


The call cannot be completed at this time or cannot be completed from this thread. For more information, see the following Remarks section.

Use the WriteWarning method to display warnings about the activity of your cmdlet. By default, warning output is discarded, although this can be configured with the WarningPreference shell variable or with the -Verbose and -Debug command-line options.

This method can be called only from within the cmdlet implementation of the BeginProcessing, ProcessRecord, and EndProcessing methods and only from that thread. If the call is made outside one of these implementations or from another thread, an InvalidOperationException exception is thrown.

Cmdlets that are in invoked from within a cmdlet (the invoked cmdlet must derive directly from the Cmdlet class) can implement the ICommandRuntime interface which can be used to override the default behavior of this method.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


Target Platforms

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