Public Property Hidden As Boolean

Dim instance As SPContentType
Dim value As Boolean

value = instance.Hidden

instance.Hidden = value

public bool Hidden { get; set; }

Imports System
Imports Microsoft.SharePoint

Module ConsoleApp

    Sub Main()
        Console.WriteLine()

        Dim oSPSite As SPSite = New SPSite("http://localhost")
        Dim oSPWeb As SPWeb = oSPSite.OpenWeb()

        ' Hide a content type from the New menu on a list.
        Dim oList As SPList = oSPWeb.Lists("Custom Document Library")
        Dim oContentType As SPContentType = oList.ContentTypes("Content Type Name")
        If (oContentType.ReadOnly Or oContentType.Sealed) Then
            Console.WriteLine("Content type cannot be modified.")
        Else
            oContentType.Hidden = True
            oContentType.Update()
            Console.WriteLine("Content type is now hidden.")
        End If

        oSPWeb.Dispose()
        oSPSite.Dispose()

        Console.WriteLine()
        Console.Write("Press ENTER to continue...")
        Console.ReadLine()
    End Sub

End Module

using System;
using Microsoft.SharePoint;

namespace Test
{
    class ConsoleApp
    {
        static void Main(string[] args)
        {
            Console.WriteLine();
            SPSite oSPSite = new SPSite("http://localhost");
            SPWeb oSPWeb = oSPSite.OpenWeb();

            // Hide a content type from the New menu on a list.
            SPList oList = oSPWeb.Lists["Custom Document Library"];
            SPContentType oContentType = oList.ContentTypes["Content Type Name"];
            if (oContentType.ReadOnly || oContentType.Sealed)
            {
                Console.WriteLine("Content type cannot be modified.");
            }
            else
            {
                oContentType.Hidden = true;
                oContentType.Update();
                Console.WriteLine("Content type is now hidden.");
            }

            oSPWeb.Dispose();
            oSPSite.Dispose();

            Console.WriteLine();
            Console.Write("Press ENTER to continue...");
            Console.ReadLine();
        }
    }
}