Private Sub SetStatusText(ByVal text As String)
        If Me.InvokeRequired Then
            Dim a As Action(Of String) = Function(s) SetStatusText(s)  ' <---- ERROR
            Me.Invoke(a, text)
        Else
            txtStatus.Text = text
        End If
    End Sub

ERROR : Expression does not produce a value. Why that error what getting? I was testing a code and that part is lambda expression.

EDIT: Solved the above error by changing the Function to Sub.

==================================================================================

Public MustInherit Class Particle
    Implements IComparable(Of Particle)      ' <----- ERROR

    '...

    Public Function CompareTo(ByVal other As Particle) As Integer
        If other Is Nothing Then
            Throw New ArgumentNullException("other")
        End If

        If Me Is other OrElse Me.Cost = other.Cost Then
            Return 0
        End If

        If Me.Cost > other.Cost Then
            Return 1
        Else
            Return -1
        End If
    End Function

End Class

ERROR: Class 'Particle' must implement 'Function CompareTo(other As ParticleSwarm.Particle) As Integer' for interface 'System.IComparable(Of Particle)'

Here, Particle and ParticleSwarm are different classes. But why that error is appearing?