Lambda或Linq方法搜索多个参数

Question

我有一个Of Of Of List和id,想查询带有多个参数的列表,以减少搜索页面上的结果.

     int SecLink = (!string.IsNullOrEmpty(Request.QueryString["Sector"])) ? Convert.ToInt32(Request.QueryString["Sector"]) : 0;
        int LocLink = (!string.IsNullOrEmpty(Request.QueryString["Location"])) ? Convert.ToInt32(Request.QueryString["Location"]) : 0;
        int IndLink = (!string.IsNullOrEmpty(Request.QueryString["Industry"])) ? Convert.ToInt32(Request.QueryString["Industry"]) : 0;
        int VacLink = (!string.IsNullOrEmpty(Request.QueryString["Vacancy"])) ? Convert.ToInt32(Request.QueryString["Vacancy"]) : 0;

        string keyword = Request.QueryString["SearchTerm"];

        var dx = new DataX();
        var lstJobs = dx.GetAllJobs().Where(x => x.SectorLink.Equals(SecLink) && x.LocationLink.Equals(LocLink) && x.IndustryLink.Equals(IndLink) && x.VacancyTypeLink.Equals(VacLink) && x.JobName.Contains(keyword)).ToList();

        if (lstJobs.Count > 0)
        {
            uiRptSearchJobs.DataSource = lstJobs;
            uiRptSearchJobs.DataBind();

            uiLitSearchResults.Text = string.Format("<h4>Search result found {0} matches</h4>", lstJobs.Count);
        }

搜索参数可能是'0',因为没有从上一页中选择,所以结果应该反映他的.

这是我传递的查询字符串:

Default.aspx?section=search&Sector=4&Location=0&Industry=0&Vacancy=0&SearchTerm=

但正如您所看到的,它们的查询字符串将随用户从上一页中选择的内容而改变.

Answer 1

如果我理解正确,你不想过滤参数的值是0吗？如果有,有两个解决方案:

1. 在您的条件中检查参数是否等于0:

   var lstJobs = dx.GetAllJobs().Where(x => 
       (SecLink == 0 || x.SectorLink.Equals(SecLink))
       && (LocLink == 0 || x.LocationLink.Equals(LocLink))
       && (IndLink == 0 || x.IndustryLink.Equals(IndLink))
       && (VacLink == 0 || x.VacancyTypeLink.Equals(VacLink))
       && x.JobName.Contains(keyword)).ToList();
   

2. Linq善良,动态构建您的查询:

       var query = dx.GetAllJobs().Where(x => x.JobName.Contains(keyword));
   
       if (SecLink != 0)
       {
           query = query.Where(x => x.SectorLink.Equals(SecLink));
       }
   
       if (LocLink != 0)
       {
           query = query.Where(x => x.LocationLink.Equals(LocLink));
       }
   
       if (IndLink != 0)
       {
           query = query.Where(x => x.IndustryLink.Equals(IndLink));
       }
   
       if (VacLink != 0)
       {
           query = query.Where(x => x.VacancyTypeLink.Equals(VacLink));
       }
   
       var lstJobs = query.ToList();