我參考以下這一篇文章，想要做所謂的Dynamic LINQ：
http://kevintsengtw.blogspot.com/2012/06/dynamic-linq-entity-framework-part3.html

public ActionResult Test1()
    using (NorthwindEntities db = new NorthwindEntities())
        var query = db.Customers
            .Where("City == @0 and Orders.Count >= @1", "London", 10)
            .OrderBy("CustomerID desc")
            .Take(10);
        ViewData.Model = query.ToList();
        return View();
然後我就把我的程式改寫成以下
public IPagedList<MemberViewModel> IPGetMemberToPaperRole(int ConferenceId, int PaperId, string Role, int? Page, string SearchKeyWord = "")
    List<MemberViewModel> mv = new List<MemberViewModel>();
    db.MemberToPapers.Where("ConferenceId == @0 AND PaperId == @1 AND Role == @2", ConferenceId, PaperId, Role)
        .Join(db.Members.Where(wm => wm.Name.Contains(@3), SearchKeyWord),
        m => m.MemberId,
        x => x.MemberId,
        (m, x) => new
            m.ConferenceId,
            m.PaperId,
            m.Role,
            x.MemberId,
            x.Name,
            x.Email
        }).ToList()
        .ForEach(o => mv.Add(new MemberViewModel
            ConferenceId = o.ConferenceId,
            PaperId = o.PaperId,
            MemberId = o.MemberId,
            Name = o.Name,
            Email = o.Email,
            RoleName = GetRole(o.Role)
    int pageNumber = (Page ?? 1);
    int pageSize = 2;
    return mv.ToPagedList(pageNumber, pageSize);
VS回報錯誤：'方法'Where'沒有任何多載使用4個引數'

不知道要如何修正才能改為Dynamic LINQ呢？

我想要做的是若SearchKeyWord有值，則搜尋出KeyWord相關的資料，若SearchKeyWord沒值，則搜尋出全部的資料。
dynamic LINQ專案是開源的,可以看一下它使用的是DynamicExpression技術

所以有一個很重要概念它不只能用在LINQ SQL,普通的集合物件LINQ Object也可以使用,這是一個很強大的功能,舉例:
	var datas = new[] { new { id = 1, value = "001" }, new { id = 2, value = "002" } };
	var result = datas.AsQueryable().Where("id=@0", 1);
	Console.WriteLine(result);
                        不過我覺得他的需求似乎並不需要Dynamic Linq。只要mv維持是IQueryable，然後根據條件再加入Where就好了，查詢並不需要一次做完。
IQueryable要等到Materialize時才會產生sql去跟資料庫查詢。（例如：呼叫ToList()方法等的時候）
                        [fillano](/users/20000108)大大是的,他不需要使用到Dynamic LINQ,而且先熟悉強類型的LINQ更重要
其實想藉由他的提問跟大家介紹Dynamic LINQ不只能用在LINQ SQL的強大功能
                            
如大大建議，是不用Dynamic Linq，改天再試做Dynamic Linq，不過目前改寫的內容只能用最笨的寫法如下：
if (!string.IsNullOrEmpty(SearchKeyWord))
    db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role)
    .Join(db.Members.Where(wm => wm.Name.Contains(SearchKeyWord)),
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    }).ToList()
    .ForEach(o => mv.Add(new MemberViewModel
        ConferenceId = o.ConferenceId,
        PaperId = o.PaperId,
        MemberId = o.MemberId,
        Name = o.Name,
        Email = o.Email,
        RoleName = GetRole(o.Role)
    db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role)
    .Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    }).ToList()
    .ForEach(o => mv.Add(new MemberViewModel
        ConferenceId = o.ConferenceId,
        PaperId = o.PaperId,
        MemberId = o.MemberId,
        Name = o.Name,
        Email = o.Email,
        RoleName = GetRole(o.Role)
嘗試著用fillano大大建議的方法，遇到許多轉型的問題。。。＞＜
var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role);
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Join(db.Members.Where(wm => wm.Name.Contains(SearchKeyWord)),
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    result = result.Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
result.ToList()
.ForEach(o => mv.Add(new MemberViewModel
    ConferenceId = o.ConferenceId,
    PaperId = o.PaperId,
    MemberId = o.MemberId,
    Name = o.Name,
    Email = o.Email,
    RoleName = GetRole(o.Role)
                        如大大建議，是不用Dynamic Linq，改天再試做Dynamic Linq，不過目前改寫的內容只能用最笨的寫法如下：
if (!string.IsNullOrEmpty(SearchKeyWord))
    db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role)
    .Join(db.Members.Where(wm => wm.Name.Contains(SearchKeyWord)),
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    }).ToList()
    .ForEach(o => mv.Add(new MemberViewModel
        ConferenceId = o.ConferenceId,
        PaperId = o.PaperId,
        MemberId = o.MemberId,
        Name = o.Name,
        Email = o.Email,
        RoleName = GetRole(o.Role)
    db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role)
    .Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    }).ToList()
    .ForEach(o => mv.Add(new MemberViewModel
        ConferenceId = o.ConferenceId,
        PaperId = o.PaperId,
        MemberId = o.MemberId,
        Name = o.Name,
        Email = o.Email,
        RoleName = GetRole(o.Role)
嘗試著用[fillano](/users/20000108)大大建議的方法，遇到許多轉型的問題。。。＞＜
var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role);
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Join(db.Members.Where(wm => wm.Name.Contains(SearchKeyWord)),
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
    result = result.Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
result.ToList()
.ForEach(o => mv.Add(new MemberViewModel
    ConferenceId = o.ConferenceId,
    PaperId = o.PaperId,
    MemberId = o.MemberId,
    Name = o.Name,
    Email = o.Email,
    RoleName = GetRole(o.Role)
                            <p>fillano大大，其實先Join db.Members，然後where下在if{}裡面我知道，也很想，但改寫方式一直遇到錯誤，實在不知道該如何改，才只能用最爛的方式寫了。。。＞＜<br/>
如果大大方便的話是否可以給我一個小小範例，真的感激不盡～</p>
<pre><code>var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role).Join(db.Members);
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Where(wm => wm.Name.Contains(SearchKeyWord))
                        <textarea class="SimpleMDE form-control comment__textarea" rows="3" name="description" cols="50">fillano大大，其實先Join db.Members，然後where下在if{}裡面我知道，也很想，但改寫方式一直遇到錯誤，實在不知道該如何改，才只能用最爛的方式寫了。。。＞＜
如果大大方便的話是否可以給我一個小小範例，真的感激不盡～
var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role).Join(db.Members);
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Where(wm => wm.Name.Contains(SearchKeyWord))
                            <p>大大真的太用心了，我只要關鍵的小小範例，大大整個資料都模擬出來，我改寫如下測試OK了，非常感謝<a href="/users/20000108" target="_blank" rel="noreferrer noopener">fillano</a>花那麼多時間幫我解答，也感謝<a href="/users/20105988" target="_blank" rel="noreferrer noopener">暐翰</a>大師～謝謝～</p>
<pre><code>var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role).Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Where(wm => wm.Name.Contains(SearchKeyWord));
result.ToList()
.ForEach(o => mv.Add(new MemberViewModel
    ConferenceId = o.ConferenceId,
    PaperId = o.PaperId,
    MemberId = o.MemberId,
    Name = o.Name,
    Email = o.Email,
    RoleName = GetRole(o.Role)
                        <textarea class="SimpleMDE form-control comment__textarea" rows="3" name="description" cols="50">大大真的太用心了，我只要關鍵的小小範例，大大整個資料都模擬出來，我改寫如下測試OK了，非常感謝[fillano](/users/20000108)花那麼多時間幫我解答，也感謝[暐翰](/users/20105988)大師～謝謝～
var result = db.MemberToPapers.Where(x => x.ConferenceId == ConferenceId && x.PaperId == PaperId && x.Role == Role).Join(db.Members,
    m => m.MemberId,
    x => x.MemberId,
    (m, x) => new
        m.ConferenceId,
        m.PaperId,
        m.Role,
        x.MemberId,
        x.Name,
        x.Email
if (!string.IsNullOrEmpty(SearchKeyWord))
    result = result.Where(wm => wm.Name.Contains(SearchKeyWord));
result.ToList()
.ForEach(o => mv.Add(new MemberViewModel
    ConferenceId = o.ConferenceId,
    PaperId = o.PaperId,
    MemberId = o.MemberId,
    Name = o.Name,
    Email = o.Email,
    RoleName = GetRole(o.Role)