如何在C#中将字符串转换为double

Question

在下面的代码中，评分生成错误

string[] allLines = File.ReadAllLines(@"Ratings.csv");

var parsed = from line in allLines
            let row = line.Split(';')
             select new
             {
                 UserId = row[0],
                 ItemId = row[1],
                 rating = row[3]
            };
var Rating = parsed.Select(x => new AddRating (x.UserId, x.ItemId,x.rating));

client.Send(new Batch(Rating));


var detailViews = parsed.Select(x => new AddDetailView(x.UserId, x.ItemId,x.rating ));

Answer 1

String st = "85.78";
Double db = Convert.ToDouble(st);

//Or With Error Hndler

try
        {
            string st = "85.78";
            Double db = Convert.ToDouble(st);
        }
catch (FormatException)
        {

            // Your error handler 

        }

Answer 2

异常告诉您问题是什么。您的构造函数需要双打，而您正在向它传递字符串。为了修复它，您必须将字符串输入解析为双精度数。

您的代码编写方式，您必须更改使用 .Select 语句的方式，以便以适当的错误处理方式解析它。

我建议将 .Select 换成 foreach，然后解析每个属性，然后实例化您的 class。

foreach (var item in parsed)
{
    double userId = 0;
    double itemId = 0;
    double rating = 0;
    double.TryParse(item.UserId, out userId);
    double.TryParse(item.ItemId, out itemId);
    double.TryParse(item.rating, out rating);

    var rating = new AddRating(userId, itemId, rating);
    //**** do whatever you want with the new object
}

如何在C#中将字符串转换为double

How to convert string to double in C#

c#

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