System.Diagnostics Namespace

The System.Diagnostics namespace provides classes that allow you to interact with system processes, event logs, and performance counters.
  • The EventLog component provides functionality to write to event logs, read event log entries, and create and delete event logs and event sources on the network. The EntryWrittenEventHandler provides a way to interact with event logs asynchronously. Supporting classes provide access to more detailed control, including: permission restrictions, the ability to specify event log types (which controls the type of default data that is written with an event log entry), and iterate through collections of event log entries. For more information about these tasks, see the EventLogPermission, EventLogEntryType, and EventLogEntryCollection classes.

  • The Process class provides functionality to monitor system processes across the network, and to start and stop local system processes. In addition to retrieving lists of running processes (by specifying either the computer, the process name, or the process id) or viewing information about the process that currently has access to the processor, you can get detailed knowledge of process threads and modules both through the Process class itself, and by interacting with the ProcessThread and ProcessModule classes. The ProcessStartInfo class enables you to specify a variety of elements with which to start a new process, such as input, output, and error streams, working directories, and command line verbs and arguments. These give you fine control over the behavior of your processes. Other related classes let you specify window styles, process and thread priorities, and interact with collections of threads and modules.

  • The PerformanceCounter class enables you to monitor system performance, while the PerformanceCounterCategory class provides a way to create new custom counters and categories. You can write to local custom counters and read from both local and remote counters (system as well as custom). You can sample counters using the PerformanceCounter class, and calculate results from successive performance counter samples using the CounterSample class. The CounterCreationData class enables you to create multiple counters in a category and specify their types. Other classes associated with the performance counter component provide access to collections of counters, counter permission, and counter types.

The System.Diagnostics namespace also provides classes that allow you to debug your application and to trace the execution of your code. For more information, see the Trace and Debug classes.

Public classBooleanSwitchProvides a simple on/off switch that controls debugging and tracing output.
Public classConditionalAttributeIndicates to compilers that a method call or attribute should be ignored unless a specified conditional compilation symbol is defined.
Public classConsoleTraceListenerDirects tracing or debugging output to either the standard output or the standard error stream.
Public classCorrelationManagerCorrelates traces that are part of a logical transaction.
Public classCounterCreationDataDefines the counter type, name, and Help string for a custom counter.
Public classCounterCreationDataCollectionProvides a strongly typed collection of CounterCreationData objects.
Public classCounterSampleCalculatorProvides a set of utility functions for interpreting performance counter data.
Public classDataReceivedEventArgsProvides data for the OutputDataReceived and ErrorDataReceived events.
Public classDebugProvides a set of methods and properties that help debug your code. This class cannot be inherited.
Public classDebuggableAttributeModifies code generation for runtime just-in-time (JIT) debugging. This class cannot be inherited.
Public classDebuggerEnables communication with a debugger. This class cannot be inherited.
Public classDebuggerBrowsableAttributeDetermines if and how a member is displayed in the debugger variable windows. This class cannot be inherited.
Public classDebuggerDisplayAttributeDetermines how a class or field is displayed in the debugger variable windows.
Public classDebuggerHiddenAttributeSpecifies the DebuggerHiddenAttribute. This class cannot be inherited.
Public classDebuggerNonUserCodeAttributeIdentifies a type or member that is not part of the user code for an application.
Public classDebuggerStepperBoundaryAttributeIndicates the code following the attribute is to be executed in run, not step, mode.
Public classDebuggerStepThroughAttributeSpecifies the DebuggerStepThroughAttribute. This class cannot be inherited.
Public classDebuggerTypeProxyAttributeSpecifies the display proxy for a type.
Public classDebuggerVisualizerAttributeSpecifies that the type has a visualizer. This class cannot be inherited.
Public classDefaultTraceListenerProvides the default output methods and behavior for tracing.
Public classDelimitedListTraceListenerDirects tracing or debugging output to a text writer, such as a stream writer, or to a stream, such as a file stream.
Public classDiagnosticsConfigurationHandlerHandles the diagnostics section of configuration files.
Public classEntryWrittenEventArgsProvides data for the EntryWritten event.
Public classEventInstanceRepresents language-neutral information for an event log entry.
Public classEventLogProvides interaction with Windows event logs.
Public classEventLogEntryEncapsulates a single record in the event log. This class cannot be inherited.
Public classEventLogEntryCollectionDefines size and enumerators for a collection of EventLogEntry instances.
Public classEventLogInstallerAllows you to install and configure an event log that your application reads from or writes to when running.
Public classEventLogPermissionAllows control of code access permissions for event logging.
Public classEventLogPermissionAttributeAllows declaritive permission checks for event logging.
Public classEventLogPermissionEntryDefines the smallest unit of a code access security permission that is set for an EventLog.
Public classEventLogPermissionEntryCollectionContains a strongly typed collection of EventLogPermissionEntry objects.
Public classEventLogTraceListenerProvides a simple listener that directs tracing or debugging output to an EventLog.
Public classEventSourceCreationDataRepresents the configuration settings used to create an event log source on the local computer or a remote computer.
Public classEventTypeFilterIndicates whether a listener should trace based on the event type.
Public classFileVersionInfoProvides version information for a physical file on disk.
Public classInstanceDataHolds instance data associated with a performance counter sample.
Public classInstanceDataCollectionProvides a strongly typed collection of InstanceData objects.
Public classInstanceDataCollectionCollectionProvides a strongly typed collection of InstanceDataCollection objects.
Public classMonitoringDescriptionAttributeSpecifies a description for a property or event.
Public classPerformanceCounterRepresents a Windows NT performance counter component.
Public classPerformanceCounterCategoryRepresents a performance object, which defines a category of performance counters.
Public classPerformanceCounterInstallerSpecifies an installer for the PerformanceCounter component.
Public classPerformanceCounterManagerPrepares performance data for the performance.dll the system loads when working with performance counters.
Public classPerformanceCounterPermissionAllows control of code access permissions for PerformanceCounter.
Public classPerformanceCounterPermissionAttributeAllows declaritive performance counter permission checks.
Public classPerformanceCounterPermissionEntryDefines the smallest unit of a code access security permission that is set for a PerformanceCounter.
Public classPerformanceCounterPermissionEntryCollectionContains a strongly typed collection of PerformanceCounterPermissionEntry objects.
Public classPresentationTraceSourcesProvides debug tracing support that is specifically targeted for Windows Presentation Foundation (WPF) applications. This is an abstract class.
Public classProcessProvides access to local and remote processes and enables you to start and stop local system processes.
Public classProcessModuleRepresents a.dll or .exe file that is loaded into a particular process.
Public classProcessModuleCollectionProvides a strongly typed collection of ProcessModule objects.
Public classProcessStartInfoSpecifies a set of values that are used when you start a process.
Public classProcessThreadRepresents an operating system process thread.
Public classProcessThreadCollectionProvides a strongly typed collection of ProcessThread objects.
Public classSourceFilterIndicates whether a listener should trace a message based on the source of a trace.
Public classSourceSwitchProvides a multilevel switch to control tracing and debug output without recompiling your code.
Public classStackFrameProvides information about a StackFrame, which represents a function call on the call stack for the current thread.
Public classStackTraceRepresents a stack trace, which is an ordered collection of one or more stack frames.
Public classStopwatchProvides a set of methods and properties that you can use to accurately measure elapsed time.
Public classSwitchProvides an abstract base class to create new debugging and tracing switches.
Public classSwitchAttributeIdentifies a switch used in an assembly, class, or member.
Public classSwitchLevelAttributeIdentifies the level type for a switch.
Public classTextWriterTraceListenerDirects tracing or debugging output to a TextWriter or to a Stream, such as FileStream.
Public classTraceProvides a set of methods and properties that help you trace the execution of your code. This class cannot be inherited.
Public classTraceEventCacheProvides trace event data specific to a thread and a process.
Public classTraceFilterProvides the base class for trace filter implementations.
Public classTraceListenerProvides the abstract base class for the listeners who monitor trace and debug output.
Public classTraceListenerCollectionProvides a thread-safe list of TraceListener objects.
Public classTraceSourceProvides a set of methods and properties that enable applications to trace the execution of code and associate trace messages with their source.
Public classTraceSwitchProvides a multilevel switch to control tracing and debug output without recompiling your code.
Public classXmlWriterTraceListenerDirects tracing or debugging output as XML-encoded data to a TextWriter or to a Stream, such as a FileStream.

Public interfaceICollectDataPrepares performance data for the performance DLL the system loads when working with performance counters.

Public structureCounterSampleDefines a structure that holds the raw data for a performance counter.

Public delegateDataReceivedEventHandlerRepresents the method that will handle the OutputDataReceived event or ErrorDataReceived event of a Process.
Public delegateEntryWrittenEventHandlerRepresents the method that will handle the EntryWritten event of an EventLog.

Public enumerationDebuggableAttribute.DebuggingModesSpecifies the debugging mode for the just-in-time (JIT) compiler.
Public enumerationDebuggerBrowsableStateProvides display instructions for the debugger.
Public enumerationEventLogEntryTypeSpecifies the event type of an event log entry.
Public enumerationEventLogPermissionAccessDefines access levels used by EventLog permission classes.
Public enumerationOverflowActionSpecifies how to handle entries in an event log that has reached its maximum file size.
Public enumerationPerformanceCounterCategoryTypeIndicates whether the performance counter category can have multiple instances.
Public enumerationPerformanceCounterInstanceLifetimeSpecifies the lifetime of a performance counter instance.
Public enumerationPerformanceCounterPermissionAccessDefines access levels used by PerformanceCounter permission classes.
Public enumerationPerformanceCounterTypeSpecifies the formula used to calculate the NextValue method for a PerformanceCounter instance.
Public enumerationProcessPriorityClassIndicates the priority that the system associates with a process. This value, together with the priority value of each thread of the process, determines each thread's base priority level.
Public enumerationProcessWindowStyleSpecified how a new window should appear when the system starts a process.
Public enumerationSourceLevelsSpecifies the levels of trace messages filtered by the source switch and event type filter.
Public enumerationThreadPriorityLevelSpecifies the priority level of a thread.
Public enumerationThreadStateSpecifies the current execution state of the thread.
Public enumerationThreadWaitReasonSpecifies the reason a thread is waiting.
Public enumerationTraceEventTypeIdentifies the type of event that has caused the trace.
Public enumerationTraceLevelSpecifies what messages to output for the Debug, Trace and TraceSwitch classes.
Public enumerationTraceOptionsSpecifies trace data options to be written to the trace output.