I want to Help vb convert to c# code

Public Function URLEncode(PlainText As String) As String
Dim pLen
pLen = Len(PlainText)
        Dim HexPart As String
        Dim z As Long
        Dim OK As Boolean
        Dim i As Long
        Dim rtags() As String
        Dim recognised As String
        recognised = "*,+,-,.,0,1,2,3,4,5,6,7,8,9,_," & "A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z," & "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z"
        rtags = Split(recognised, ",")
        Dim Ptags() As String
        ReDim Ptags(pLen)
        For i = 1 To Len(PlainText)
            Ptags(i) = Mid(PlainText, i, 1)
            OK = False
            For z = 0 To UBound(rtags)
                If Ptags(i) = rtags(z) Then
                    OK = True: Exit For
                End If
            Next
            If Not OK Then
                HexPart = Hex(Asc(Ptags(i)))
                If Len(HexPart) = 1 Then HexPart = "0" + HexPart
                Ptags(i) = "%" + HexPart
            End If
        Next
        URLEncode = Join(Ptags, "")
    End Function