Question

在我的视图中，我有一个带有一些服务器名称列表的多选。服务器数量将是动态的并且经常变化。

<select name="servers" class="selectpicker" multiple data-live-search="true">
  <optgroup label="Prod5">
    <option>VS12</option>
    <option>...</option>                
  </optgroup>
  <optgroup label="UAT6">
    <option>VS13</option>
    <option>...</option>                        
  </optgroup>
</select>

在控制器中，我需要针对某些静态数量的KPIKey和服务器名称（kpi.KPIserver）过滤db，用户将从多个select中选择。如何在下面的where子句中添加动态数量的KPIserver检查，例如

其中kpi.KPIkey ==＆＃34; CPU使用率＆＃34; || kpi.KPIkey ==＆＃34; I / O操作＆＃34; ＆安培;＆安培; kpi.KPIserver ==＆＃34; VS12＆＃34; || kpi.KPIserver ==＆＃34; VS13＆＃34; || kpi.KPIserver == ...

[HttpPost]
    public ActionResult Index(FormCollection fs)
    {

        IEnumerable<kpi_master> allKPI = null;

        try
        {               
            allKPI = from kpi in db.kpi_masters
                     where kpi.KPIkey == "CPU usage" || kpi.KPIkey == "I/O operations"                                                  
                     select kpi;
        }
        catch (Exception e) { log.Error("KPI POST error: " + e.Message); }

        return View(allKPI);

    }

Answer 1

如果您正在检查一定数量的字段，那么这很容易。

var keys = new List<string>()  { "CPU usage", "I/O operations" };
var servers = new List<string>() { "VS13", "SERVERX" };

.....

allKPI = allKPI = from kpi in db.kpi_masters
                  where keys.Contains(kpi.KPIkey) || servers.Contains(kpi.KPIserver)
                  select kpi;

Answer 2

如果子句数是动态的，则使用linq扩展方法。然后像

var result = collection. Where (o => contional clause 1);
foreach (var extraclause in dynamicClauses)
{
    result = result.Where (o => extraclause (o));
}

因此，您可以动态添加子句，并且只有在枚举集合（结果）时才会执行查询。如果要强制执行，请立即添加

var final = result.ToArray ();

MVC3动态检查where子句的数量

2 个答案: