<SharePointPermissionAttribute(SecurityAction.LinkDemand, ObjectModel:=True)> _
<SharePointPermissionAttribute(SecurityAction.InheritanceDemand, ObjectModel:=True)> _
Public NotInheritable Class SPContentType

Dim instance As SPContentType

[SharePointPermissionAttribute(SecurityAction.LinkDemand, ObjectModel=true)] 
[SharePointPermissionAttribute(SecurityAction.InheritanceDemand, ObjectModel=true)] 
public sealed class SPContentType

Imports System
Imports Microsoft.SharePoint

Module Test

#Region "fields"
   Private requestUrl As String = "http://localhost"

   ' Name and type of content type to create.
   Private ctName As String = "Customer"
   Private parentId As SPContentTypeId = SPBuiltInContentTypeId.Contact

   ' Name and type of site column to create.
   Private fldName As String = "LastOrder"
   Private fldType As SPFieldType = SPFieldType.DateTime

   ' Name, type, and description of list to create.
   Private lstName As String = "Customers"
   Private lstType As SPListTemplateType = SPListTemplateType.Contacts
   Private lstDesc As String = "A list of customers."
#End Region

   Sub Main()
      Using site As SPSite = New SPSite(requestUrl)
         Using web As SPWeb = site.OpenWeb()
            If ValidNames(web) Then
               ' Create a new site content type.
               Dim cts As SPContentTypeCollection = web.ContentTypes
               Dim ct As New SPContentType(cts(parentId), cts, ctName)

               ' Add the content type to the site collection.
               cts.Add(ct)
               Console.WriteLine( _
                  "Added {0} content type to site collection.", ct.Name)

               ' Create a site field to link to.
               Dim fields As SPFieldCollection = web.Fields
               fldName = fields.Add(fldName, fldType, False)
               Console.WriteLine("Created {0} site column.", fldName)

               ' Link the content type to the field.
               Dim field As SPField = fields.GetField(fldName)
               Dim fieldLink As SPFieldLink = New SPFieldLink(field)
               ct.FieldLinks.Add(fieldLink)
               Console.WriteLine( _
                  "Linked {0} content type to {1} column.", _
                  ct.Name, field.InternalName)

               ' Commit changes to the database.
               ct.Update()

               ' Create a list.
               Dim lists As SPListCollection = web.Lists
               Dim listID As Guid = lists.Add(lstName, lstDesc, lstType)
               Dim list As SPList = lists(listID)
               list.OnQuickLaunch = True
               list.Update()
               Console.WriteLine("Created {0} list.", list.Title)

               ' Apply the new content type to the list.
               list.ContentTypesEnabled = True
               If list.IsContentTypeAllowed(ct) Then
                  ' Add the new content type.
                  Dim lstCT As SPContentType = list.ContentTypes.Add(ct)
                  ' Remove the default content type.
                  list.ContentTypes(0).Delete()
                  ' Commit changes to the list.
                  list.Update()
                  Console.WriteLine("Applied {0} content type to {1} list.", _
                                    lstCT.Name, list.Title)
               Else
                  Console.WriteLine("{0} list does not allow {1} content type.", _
                                    list.Title, ct.Name)
               End If
            End If
         End Using
      End Using
      Console.Write(vbCrLf + "Press ENTER to continue...")
      Console.ReadLine()
   End Sub

   ' Checks for duplicate content type, field, and list names.
   Private Function ValidNames(ByRef web As SPWeb) As Boolean
      Dim valid As Boolean = True

      ' Duplicate content type name?
      If web.AvailableContentTypes(ctName) IsNot Nothing Then
         valid = False
         Console.WriteLine("Duplicate content type name.")
      End If

      ' Invalid characters in content type name?
      Try
         SPContentType.ValidateName(ctName)
      Catch ex As SPException
         valid = False
         Console.WriteLine("Invalid character in content type name.")
      End Try

      ' Duplicate field name?
      If web.Fields.ContainsField(fldName) Then
         valid = False
         Console.WriteLine("Duplicate field name.")
      End If

      ' Duplicate list name?
      Try
         Dim list As SPList = web.Lists(lstName) ' Exception if not found
         valid = False
         Console.WriteLine("Duplicate list name.")
      Catch ex As ArgumentException
         ' List name does not exist.
      End Try

      Return valid
   End Function

End Module

using System;
using Microsoft.SharePoint;

namespace Test
{
   class ConsoleApp
   {
      #region fields
      private static string requestUrl = "http://localhost";

      // Name and type of content type to create.
      private static string ctName = "Customer";
      private static SPContentTypeId parentId = SPBuiltInContentTypeId.Contact;

      // Name and type of site column to create.
      private static string fldName = "LastOrder";
      private static SPFieldType fldType = SPFieldType.DateTime;

      // Name, type, and description of list to create.
      private static string lstName = "Customers";
      private static SPListTemplateType lstType = SPListTemplateType.Contacts;
      private static string lstDesc = "A list of customers.";
      #endregion

      static void Main(string[] args)
      {
         using (SPSite site = new SPSite(requestUrl))
         {
            using (SPWeb web = site.OpenWeb())
            {
               // Check for duplicate content type, field, and list names.
               if (ValidNames(web))
               {
                  // Create a new site content type.
                  SPContentTypeCollection cts = web.ContentTypes;
                  SPContentType ct = new SPContentType(cts[parentId], // parent
                                                       cts,           // collection
                                                       ctName);       // name

                  // Add the content type to the site collection.
                  cts.Add(ct);
                  Console.WriteLine(
                      "Added {0} content type to site collection.", ct.Name);

                  // Create a site field to link to.
                  SPFieldCollection fields = web.Fields;
                  fldName = fields.Add(fldName, fldType, false);
                  Console.WriteLine("Created {0} site column.", fldName);

                  // Link the content type to the field.
                  SPField field = fields.GetField(fldName);
                  SPFieldLink fieldLink = new SPFieldLink(field);
                  ct.FieldLinks.Add(fieldLink);
                  Console.WriteLine(
                            "Linked {0} content type to {1} column.",
                             ct.Name, field.InternalName);

                  // Commit changes to the database.
                  ct.Update();

                  // Create a list.
                  SPListCollection lists = web.Lists;
                  Guid listID = lists.Add(lstName, lstDesc, lstType);
                  SPList list = lists[listID];
                  list.OnQuickLaunch = true;
                  list.Update();
                  Console.WriteLine("Created {0} list.", list.Title);

                  // Apply the new content type to the list.
                  list.ContentTypesEnabled = true;
                  if (list.IsContentTypeAllowed(ct))
                  {
                     // Add the new content type.
                     SPContentType lstCT = list.ContentTypes.Add(ct);
                     // Remove the default content type.
                     list.ContentTypes[0].Delete();
                     // Commit changes to the list.
                     list.Update();
                     Console.WriteLine("Applied {0} content type to {1} list.",
                                        lstCT.Name, list.Title);
                  }
                  else
                  {
                     Console.WriteLine("{0} list does not allow {1} content type.",
                                        list.Title, ct.Name);
                  }

               }
            }
         }
         Console.Write("\nPress ENTER to continue...");
         Console.ReadLine();
      }

      // Checks for duplicate content type, field, and list names.
      static bool ValidNames(SPWeb web)
      {
         bool valid = true;

         // Duplicate content type name?
         if (web.AvailableContentTypes[ctName] != null)
         {
            valid = false;
            Console.WriteLine("Duplicate content type name.");
         }

         // Invalid characters in content type name?
         try
         {
            SPContentType.ValidateName(ctName);
         }
         catch (SPException ex)
         {
            Console.WriteLine("Invalid character in content type name.");
         }


         // Duplicate field name?
         if (web.Fields.ContainsField(fldName))
         {
            valid = false;
            Console.WriteLine("Duplicate field name.");
         }

         // Duplicate list name?
         try
         {
            SPList list = web.Lists[lstName]; // Exception if not found
            valid = false;
            Console.WriteLine("Duplicate list name.");
         }
         catch (ArgumentException ex)
         {
            // List name does not exist.
         }

         return valid;
      }
   }
}