如何在 linq where 中使用 TryParse

Question

        else{ 
            if(a.Item2 == ">"){
                    result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && double.TryParse(y.Value,out double res) == double.TryParse(a.Item3,out double res1)));
                //result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) > Convert.ToDouble(a.Item3)));    
            }
            else if(a.Item2 == "<")
                result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) < Convert.ToDouble(a.Item3)));
            else if(a.Item2 == "<=")
                result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) <= Convert.ToDouble(a.Item3)));
            else if(a.Item2 == ">=")
                result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) >= Convert.ToDouble(a.Item3)));
            else if(a.Item2 == "==")
                result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) == Convert.ToDouble(a.Item3)));
            else if(a.Item2 == "!=")
                result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 && Convert.ToDouble(y.Value) != Convert.ToDouble(a.Item3)));
            else
                 throw new Exception("Comparison operator not found");          
        }

如何在上述代码情况下使用 double.TryParse 代替 Convert.ToDouble，因为我不知道如何使用输出值进行比较。我想使用 TryParse，因为我收到以下错误消息：

input string was not in a correct format

我如何在当前的情况下实现这一点？

Answer 1

有点 long-winded，但假设您只想 return 可以将值解析为双精度的行：

result = dict.Where(x => x.Value.Any(y => y.Key == a.Item1 
     && double.TryParse(y.Value,out double res)  // Value can be parsed
     && double.TryParse(a.Item3,out double res1) // Item3 can be parsed
     && res == res1)); // the 2 parsed results match

如何在 linq where 中使用 TryParse

How to use TryParse in linq where

c#

linq

tryparse

where-clause