将Linq查询返回到KeyValuePair的列表中

Question

我正在将我的图表应用程序从预设数据转换为使用数据库。

以前我用的是这样的：

var data = new Dictionary<string, double>();    

switch (graphselected) 
{   
case "1": 
    data = new Dictionary<string, double> 
    { 
     {"Dave", 10.023f}, 
     {"James", 20.020f}, 
     {"Neil", 19.203f}, 
     {"Andrew", 4.039f}, 
     {"Steve", 5.343f} 
    }; 
    break; 
case "2": 
    data = new Dictionary<string, double> 
    { 
     {"Dog", 10.023f}, 
     {"Cat", 20.020f}, 
     {"Owl", 19.203f}, 
     {"Rat", 16.039f}, 
     {"Bat", 27.343f} 
    }; 
    break; 
//etc... 
} 

// Add each item in data in a foreach loop 
foreach (var item in list) 
{ 
    // Adjust the Chart Series values used for X + Y 
    seriesDetail.Points.AddXY(item.Key, item.Value); 
} 

这就是我想要做的事：

var list = new List<KeyValuePair<string, double>>(); 

switch (graphselected) 
{ 
case "1": 
    var query = (from x in db2.cd_CleardownCore 
       where x.TimeTaken >= 10.0 
       select new { x.IMEI, x.TimeTaken }).ToList(); 
    list = query;     
    break; 
//... 
} 

我的代码错误对：

list = query; 

，出现错误：

Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' 
to 'System.Collections.Generic.List<System.Collections.Generic.KeyValuePair<string,double>>' 

如何实现转换？

Answer 1

如果你想要一个keyvaluepair列表，你需要很好地构建它，keyvaluepairs！在选择这样替换你匿名对象：

select new KeyValuePair<string,double>(x.IMEI,x.TimeTaken) 

编辑为您的新问题：

var q = (from x in db2.cd_CleardownCore 
      where x.TimeTaken >= 10.0 
      select new { x.IMEI, x.TimeTaken }); 
var query = q.AsEnumerable() // anything past this is done outside of sql server 
     .Select(item=>new KeyValuePair<string,double?>(item.IMEI,item.TimeTaken)) 
     .ToList();