/// <summary>
/// 通用行的Service layer實作
/// </summary>
/// <typeparam name="T">主要的Entity形態</typeparam>
public class GenericService<T> : IService<T>
    where T : class
{
....
	/// <summary>
    /// 處理在Index ViewModel所需要做的事情
    /// </summary>
    /// <typeparam name="TSearchForm">搜索form的形態</typeparam>
    /// <typeparam name="TPageResult">搜索結果的形態</typeparam>
    /// <param name="searchViewModel">搜索相關的viewmodel</param>
    /// <param name="includes">需要Include進來的其他Entity</param>
    public virtual void ProcessIndexViewModel<TSearchForm, TPageResult>(ISearchViewModelBase<TSearchForm, TPageResult> searchViewModel,  
        params System.Linq.Expressions.Expression<Func<T, object>>[] includes) 
        where TSearchForm : ISearchFormViewModelBase, new()
    {
        var data = db.Repository<T>().Reads();

        foreach (var item in includes)
        {
            data.Include(item);
        }
		
		SearchViewModelProcess.ApplySearchForm<T, TSearchForm, TPageResult>(data,
                    searchViewModel);
    }
....
}

/// <summary>
/// 把Search Form Viewmodel的OrderBy和Where條件apply上去。
/// 會把最終內容儲存到SearchViewModelBase.Result裡面。
/// </summary>
/// <typeparam name="T">EF 的Entity</typeparam>
/// <typeparam name="TSearchForm">Search Form ViewModel的Type</typeparam>
/// <typeparam name="TPageResult">Search結果的VieModel type</typeparam>
/// <param name="data">原始的IQueryable</param>
/// <param name="searchForm">Search Form ViewModel</param>
public static void ApplySearchForm<T, TSearchForm, TPageResult>(IQueryable<T> data, ISearchViewModelBase<TSearchForm, TPageResult> searchForm)
     where TSearchForm : ISearchFormViewModelBase, new()
{
    data = data.DynamicWhere(searchForm.SearchForm);

    ApplyOrderByAndToPageResult<T, TSearchForm, TPageResult>(data, searchForm);
}

/// <summary>
/// 依照Search Form ViewModel的值來設定Where的內容。
/// </summary>
/// <typeparam name="T">通常是EF的Entity</typeparam>
/// <param name="data">要被處理的資料</param>
/// <param name="searchForm">Search Form Viewmodel的值</param>
/// <returns>有增加OrderBy的IQueryable</returns>
public static IQueryable<T> DynamicWhere<T>(this IQueryable<T> data, ISearchFormViewModelBase searchForm)
{
    var properties = searchForm.GetType().GetProperties
						(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public)
                        .Where(x => (x.GetGetMethod().GetBaseDefinition() == x.GetGetMethod())).ToArray(); // where 條件是用來避免override的property （例如：OrderByColumnName）也被算進去。

    string whereCalus = string.Empty;
    string andOperator = string.Empty;
    List<object> propertiesValue = new List<object>();

    for (int i = 0; i < properties.Length; i++)
    {
        var value = properties[i].GetValue(searchForm);

        if (string.IsNullOrEmpty(value.NonNullString()) == false)
        {
            whereCalus = string.Format("{0}{1} {2} = @{3}", whereCalus, andOperator,
                    properties[i].Name, propertiesValue.Count);

            andOperator = " and";

            propertiesValue.Add(value);
        }
    }

    if (string.IsNullOrEmpty(whereCalus) == false)
    {
        data = data.Where(whereCalus, propertiesValue.ToArray());
    }

    return data;
}

/// <summary>
/// Apply Orderby並且把最後結果塞到SearchViewModelBase.Result裡面。
/// </summary>
/// <typeparam name="T">EF 的Entity</typeparam>
/// <typeparam name="TSearchForm">Search Form ViewModel的Type</typeparam>
/// <typeparam name="TPageResult">Search結果的VieModel type</typeparam>
/// <param name="data">原始的IQueryable</param>
/// <param name="searchForm">Search Form ViewModel</param>
private static void ApplyOrderByAndToPageResult<T, TSearchForm, TPageResult>(IQueryable<T> data, 
    ISearchViewModelBase<TSearchForm, TPageResult> searchForm) where TSearchForm : ISearchFormViewModelBase, new()
{
    if (searchForm.SearchForm.IsAscending)
    {
        data = data.OrderBy(searchForm.SearchForm.OrderByColumnName);
    }
    else
    {
        data = data.OrderBy(searchForm.SearchForm.OrderByColumnName + " descending");
    }

    searchForm.Result = data.Project().To<TPageResult>().ToPagedList(searchForm.SearchForm.Page, searchForm.SearchForm.PageSize);
}

public ActionResult Index(Index searchViewModel)
{
    service.ProcessIndexViewModel(searchViewModel);

    return View(searchViewModel);
}