.NET Framework 4.6 and 4.5
Gets the state of the Carrier Detect line for the port.
Public ReadOnly Property CDHolding As Boolean
Type: System.Booleantrue if the carrier is detected; otherwise, false.
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.
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.
Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0
.NET Framework Client Profile
Supported in: 4, 3.5 SP1