log4net SDK Reference |

# MDC Class

Implementation of Mapped Diagnostic Contexts.

For a list of all members of this type, see MDC Members.

System.Object
log4net.MDC

[Visual Basic]
NotInheritable Public Class MDC
[C#]
public sealed class MDC

#### Thread Safety

This type is safe for multithreaded operations.

#### Remarks

> Note

> The MDC is deprecated and has been replaced by the Properties. The current MDC implementation forwards to the `ThreadContext.Properties`.

The MDC class is similar to the NDC class except that it is based on a map instead of a stack. It provides mapped diagnostic contexts. A Mapped Diagnostic Context, or MDC in short, is an instrument for distinguishing interleaved log output from different sources. Log output is typically interleaved when a server handles multiple clients near-simultaneously.

The MDC is managed on a per thread basis.

#### Requirements

Namespace: log4net

Assembly: log4net (in log4net.dll)

#### See Also

MDC Members | log4net Namespace