QuickOPC User's Guide and Reference
IsNull Property (EventSource)



OpcLabs.BaseLib Assembly > OpcLabs.BaseLib.ComponentModel.Referencing Namespace > EventSource Class : IsNull Property
Determines whether this event source object is null.
Syntax
'Declaration
 
<BrowsableAttribute(False)>
<DefaultValueAttribute(True)>
Public ReadOnly Property IsNull As Boolean
'Usage
 
Dim instance As EventSource
Dim value As Boolean
 
value = instance.IsNull
[Browsable(false)]
[DefaultValue(true)]
public bool IsNull {get;}
[Browsable(false)]
[DefaultValue(true)]
public:
property bool IsNull {
   bool get();
}
Remarks
The event source is null when its source component and extender event provider are null, and the source path is empty.
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also