Getting Custom Columns from SharePoint list

Getting Custom Columns from SharePoint list

Dim sReturnValue As String = Nothing

    Dim sReturnValuec As String = Nothing
    Dim listService As New WssListsSvc.Lists()
    Dim m_credentials  As ICredentials = New Net.NetworkCredential(UserId, Pwd, Domain)
    listService.Credentials = m_credentials
    Dim result As XmlNode = listService.GetList(sLibName)
    For Each ndField As XmlNode In result.FirstChild.ChildNodes
        Dim IsReadOnly As String = String.Empty

        Dim name As String = String.Empty

        If ndField.Attributes("ReadOnly") IsNot Nothing Then

           IsReadOnly = DirectCast(ndField.Attributes("ReadOnly").Value, String)
        End If
        If Not IsReadOnly = "TRUE" Then
            If ndField.Attributes("DisplayName") IsNot Nothing Then
                 name = DirectCast(ndField.Attributes("DisplayName").Value, String)
            End If                        If sTagType.ToLower = "custom" Then
                 Dim SourceID = DirectCast(ndField.Attributes("SourceID").Value, String)
                 If SourceID.Contains("sharepoint") = False Then

                     sReturnValue = name & "," & sReturnValue

                 End If
            Else                                    sReturnValue = name & "," & sReturnValue                          End If

        End If

    Next

Return sReturnValue

C# Version

string sReturnValue = null;
string sReturnValuec = null;
WssListsSvc.Lists listService = new WssListsSvc.Lists();
ICredentials m_credentials = new System.Net.NetworkCredential(UserId, Pwd, Domain);
listService.Credentials = m_credentials;
XmlNode result = listService.GetList(sLibName);
foreach (XmlNode ndField in result.FirstChild.ChildNodes) {
 string IsReadOnly = string.Empty;
 string name = string.Empty;
 if (ndField.Attributes("ReadOnly") != null) {
  IsReadOnly = (string)ndField.Attributes("ReadOnly").Value;
 }
 if (!(IsReadOnly == "TRUE")) {
  if (ndField.Attributes("DisplayName") != null) {
   name = (string)ndField.Attributes("DisplayName").Value;
  }
  if (sTagType.ToLower == "custom") {
   dynamic SourceID = (string)ndField.Attributes("SourceID").Value;
   if (SourceID.Contains("sharepoint") == false) {
    sReturnValue = name + "," + sReturnValue;
   }
  } else {
   sReturnValue = name + "," + sReturnValue;
  }
 }
}

Notes :

1.: UserId, Pwd, Domain, sTagType, sLibName are string variables used in the function.
2.: sTagType Contains the values “All” or “Custom”. If all is passed then all the
columns are retrieved and if custom is selected then Custom Columns Comma separated
list is returned.