C# Linq，排除SQL空值

我正在生成一个饼图，目前我有以下变量，如何排除空记录？它可以工作，但在饼图中包含空值

var PieChartData1 = from T1 in Result
                    group T1 by T1.Reasons  into G1
                    orderby count ascending
                    select new { G1.Key, Count = G1.Count()  };

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在使用

where

子句之前，添加

where

子句以过滤

null

值-这里我假设

T1

或

T1。原因可以是
null
：

var PieChartData1 = from T1 in Result
                        where T1 != null && T1.Reasons != null
                        group T1 by T1.Reasons into G1
                        orderby count ascending
                        select new { G1.Key, Count = G1.Count() };

我还怀疑
orderby count ascending
应该是
orderby G1.count（）ascending
如果T1为空，请使用HasValue属性

var PieChartData1 = from T1 in Result
                        where T1.HasValue
                        group T1 by T1.Reasons into G1
                        orderby count ascending
                        select new { G1.Key, Count = G1.Count() };

也可以使用lambda表达式编写：

var pieChartData = Result.Where(r => r.Reason != null)
                         .GroupBy(r => r.Reason)
                         .OrderBy(g => g.Count())
                         .Select(g => new { g.Key, Count = g.Count() });

添加Where子句以筛选出空Where原因！=无效的我得到一个错误（原因在当前上下文中不存在），它不应该是
where T1.Reasons！=空值
？@Rufus L，这很有效！非常感谢。事实上，我用了>>哪里T1.原因！=谢谢!！事实上，我用了>>哪里T1.原因！=null…>>其中T1.HasValue（）似乎不起作用
var pieChartData = Result.Where(r => r.Reason != null)
                         .GroupBy(r => r.Reason)
                         .OrderBy(g => g.Count())
                         .Select(g => new { g.Key, Count = g.Count() });