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SerialPort.CDHolding Property

Gets the state of the Carrier Detect line for the port.

Namespace:  System.IO.Ports
Assembly:  System (in System.dll)

[BrowsableAttribute(false)]
public bool CDHolding { get; }

Property Value

Type: System.Boolean
true if the carrier is detected; otherwise, false.

ExceptionCondition
IOException

The port is in an invalid state.

- or -

An attempt to set the state of the underlying port failed. For example, the parameters passed from this SerialPort object were invalid.

InvalidOperationException

The stream is closed. This can occur because the Open method has not been called or the Close method has been called.

This property can be used to monitor the state of the carrier detection line for a port. No carrier usually indicates that the receiver has hung up and the carrier has been dropped.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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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