Question

我有一个查询，我从一些选项中编写它，比如

#include <dirent.h>
#include <vector>
#include <cstring>    

void GetReqDirs(const std::string& path, std::vector<string>& files,const bool showHiddenDirs = false){
    DIR *dpdf;
    struct dirent *epdf;
    dpdf = opendir(path.c_str());
    if (dpdf != NULL){
        while ((epdf = readdir(dpdf)) != NULL){
            if(showHiddenDirs ? (epdf->d_type==DT_DIR && string(epdf->d_name) != ".." && string(epdf->d_name) != "." ) : (epdf->d_type==DT_DIR && strstr(epdf->d_name,"..") == NULL && strstr(epdf->d_name,".") == NULL ) ){
                GetReqDirs(path+epdf->d_name+"/",files, showHiddenDirs);
            }
            if(epdf->d_type==DT_REG){
                files.push_back(path+epdf->d_name);
            }
        }
    }
    closedir(dpdf);
}

我怎样才能在一次尝试中针对LINQ over entity-framework-6做到这一点？

Answer 1

是的，你可以。你可以链接几个。所有操作。所以你可以像写

一样写smt

    var set = MySet;
    if (cond_1) {
      set  = set.Where(a=>...);
    }
    if (cond_2) {
      set  = set.Where(a=>...);
    }
    set.ToList()

等

Answer 2

您可以通过使用IQueryAble来实现。这个例子可以帮到你：

//Define your query without executing it.                  
IQueryable<YourEntityType> query= (from s in Context.MyTable select s);

if(options1)
//Add a where clause to your IQueryable
  query= query.Where(p=> p.SomeProperty == "Something");

if(options2)
//Add another where clause to your IQueryable
 query= query.Where(p=> p.SomeProperty == "Something else");

//Executes the query depending your options.
var Result = query.ToList();

通过LINQ实体框架查询组合

2 个答案: