Use IsDefined, taking a ParameterInfo as a parameter. : ParameterInfo « Reflection « VB.Net Tutorial

1. VB.Net Tutorial
2. Reflection
3. ParameterInfo

Imports System
Imports System.Reflection

Module DemoModule
    Public Class TestClass
        Public Sub Method1(ByVal ParamArray args As String())
        End Sub
    End Class

    Sub Main()
        Dim clsType As Type = GetType(TestClass)

        Dim mInfo As MethodInfo = clsType.GetMethod("Method1")

        Dim pInfo() As ParameterInfo = mInfo.GetParameters()

        Dim isDef As Boolean = Attribute.IsDefined(pInfo(0),GetType(ParamArrayAttribute))


    End Sub
End Module