using (SPWeb oWebsite = new SPSite("http://MyServer/sites/MySiteCollection/MyWebSite").OpenWeb())
{
    SPList oList = oWebsite.GetList("MyWebSite/Lists/MyList");
    SPFieldCollection collFields = oWebsite.Fields;
    //新建一个网站栏
    string strNewColumn = collFields.Add("出处", SPFieldType.Text, false);
    //添加到网站内容类型“消息”中
    SPFieldLink oFieldLink = new SPFieldLink(fields[strNewColumn]);
    SPContentType oContentType = oList.ContentTypes["消息"];
    oContentType.FieldLinks.Add(oFieldLink);

oContentType.Update(true);
}

using System;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Workflow;

namespace TestWorkflowAssociation
{
    class ConsoleAdd
    {
        static void Main(string[] args)
        {
            Console.WriteLine();
            SPSite siteCollection = new SPSite("http://sp2010u/sites/contoso/Docs");
            SPWeb site = siteCollection.OpenWeb();

SPContentType siteContentType = site.ContentTypes["费用报告"];
            string taskListTitle = "任务";
            string historyListTitle = "工作流历史记录";
            string workflowName = "红-黄-绿";

// 获取一个模板.
            SPWorkflowTemplate workflowTemplate = null;
            foreach (SPWorkflowTemplate template in site.WorkflowTemplates)
            {
                workflowTemplate = template;

// 这里找一个自带的模板.
                if (workflowTemplate.Name == "三态") break;
            }
            if (workflowTemplate != null)
            {
                // 创建一个关联.
                SPWorkflowAssociation workflowAssociation = SPWorkflowAssociation.CreateWebContentTypeAssociation(workflowTemplate, workflowName, taskListTitle, historyListTitle);

// 添加一个关联到该内容类型，如果关联已存在则更新它.
                Console.Write("工作流 {0} 已关联 ", workflowAssociation.Name);
                if (siteContentType.WorkflowAssociations.GetAssociationByName(workflowAssociation.Name, site.Locale) == null)
                {
                    siteContentType.WorkflowAssociations.Add(workflowAssociation);
                    Console.WriteLine("添加.");
                }
                else
                {
                    siteContentType.WorkflowAssociations.Update(workflowAssociation);
                    Console.WriteLine("更新.");
                }

// 将工作流关联更新推送到子代内容类型.
                siteContentType.UpdateWorkflowAssociationsOnChildren(false,  // 不需要生成完整变更清单
                                                                     true,   // 推送到继承的子代网站内容类型
                                                                     true,   // 推送到列表内容类型
                                                                     false); // 如果遇到密封或只读内容类型不抛异常  
            }
            site.Dispose();
            siteCollection.Dispose();

Console.WriteLine();
            Console.Write("任意键继续...");
            Console.ReadLine();
        }
    }
}

using System;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Workflow;

namespace TestWorkflowAssociation
{
    class ConsoleDel
    {
        static void Main(string[] args)
        {
            using (SPSite site = new SPSite("http://sp2010u/sites/contoso/Docs"))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    string ctName = "费用报告";
                    string wfName = "红-黄-绿";

SPContentType contentType = web.ContentTypes[ctName];
                    if (null != contentType)
                    {
                        SPWorkflowAssociation wfAssociation =
                            contentType.WorkflowAssociations.GetAssociationByName(wfName, web.Locale);

if (null != wfAssociation)
                        {
                            // 移除该工作流关联.
                            contentType.WorkflowAssociations.Remove(wfAssociation);
                            Console.WriteLine("与工作流 {0} 的关联已移除.", wfAssociation.Name);
                        }
                        else
                        {
                            Console.WriteLine("名为 {0} 的工作流关联未找到.", wfName);
                        }
                    }
                    else
                    {
                        Console.WriteLine("内容类型 {0} 不存在.", ctName);
                    }
                    // 将工作流关联更新推送到子代内容类型.
                    contentType.UpdateWorkflowAssociationsOnChildren(false, true, true, false); 
                }
            }
            Console.Write("\n任意键继续...");
            Console.ReadLine();
        }
    }
}