OPC Studio User's Guide and Reference
IsValidInVariant Method



OpcLabs.BaseLib Assembly > OpcLabs.BaseLib.ComInterop Namespace > VarTypeUtilities Class : IsValidInVariant Method
A VarType to be tested.

Because the VarType has an implicit conversion from System.Int32 and VarTypes, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use an integer (representing the numerical value of the COM VARTYPE), or an element of the VarTypes enumeration (or an allowed combination of VarTypes flags) in place of this parameter, and the corresponding data type specification will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the VarType Constructor(Int32) or VarType Constructor(VarTypes) constructor instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

Determines whether the given VarType can be used in a Variant.
Syntax
'Declaration
 
<PureAttribute()>
Public Shared Function IsValidInVariant( _
   ByVal varType As VarType _
) As Boolean
'Usage
 
Dim varType As VarType
Dim value As Boolean
 
value = VarTypeUtilities.IsValidInVariant(varType)
[Pure()]
public static bool IsValidInVariant( 
   VarType varType
)
[Pure()]
public:
static bool IsValidInVariant( 
   VarType^ varType
) 

Parameters

varType
A VarType to be tested.

Because the VarType has an implicit conversion from System.Int32 and VarTypes, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use an integer (representing the numerical value of the COM VARTYPE), or an element of the VarTypes enumeration (or an allowed combination of VarTypes flags) in place of this parameter, and the corresponding data type specification will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the VarType Constructor(Int32) or VarType Constructor(VarTypes) constructor instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

true if the VarType can be used in a Variant; false otherwise.
Exceptions
ExceptionDescription

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks

This method is pure, i.e. it does not have observable side effects.

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