在CsvHelper中处理错误的CSV记录 [英] Handling bad CSV records in CsvHelper

问题描述

我希望能够遍历CSV文件中的所有记录，并将所有良好记录添加到一个集合中，并分别处理所有不良"记录.我似乎无法做到这一点，我想我一定很想念东西.

I would like to be able to iterate through all records in a CSV file and add all the good records to one collection and handle all the "bad" ones separately. I don't seem to be able to do this and I think I must be missing something.

如果我尝试捕获BadDataException，则后续读取将失败，这意味着我无法继续读取该文件的其余部分-

If I attempt to catch the BadDataException then subsequent reads will fail meaning I cannot carry on and read the rest of the file -

while (true)
{
    try
    {
        if (!reader.Read())
            break;

        var record = reader.GetRecord<Record>();
        goodList.Add(record);
    }
    catch (BadDataException ex)
    {
        // Exception is caught but I won't be able to read further rows in file
        // (all further reader.Read() result in same exception thrown)
        Console.WriteLine(ex.Message);
    }
}

讨论的另一个选项是设置BadDataFound回调操作来处理它-

The other option discussed is setting the BadDataFound callback action to handle it -

reader.Configuration.BadDataFound = x =>
{
    Console.WriteLine($"Bad data: <{x.RawRecord}>");
};

尽管调用了回调，但不良记录仍然出现在我的良好列表"中

However although the callback is called the bad record still ends up in my "good list"

在将记录添加到列表中之前，是否可以通过某种方式查询读者以查看记录是否良好?

Is there some way I can query the reader to see if the record is good before adding it to my list?

在此示例中，我的记录定义为-

For this example my Record definition is -

class Record
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}

和数据(第一行坏，第二行好)-

And the data (first row bad, second row good) -

"Jo"hn","Doe",43
"Jane","Doe",21

有趣的是，使用MissingFieldException处理丢失的字段似乎完全按照我的意愿运行-引发了异常，但后续行仍然可以读取.

Interestingly handling a missing field with MissingFieldException seems to function exactly as I would like - the exception is thrown but subsequent rows are still read ok.

推荐答案

这是示例我提供了.

void Main()
{
    using (var stream = new MemoryStream())
    using (var writer = new StreamWriter(stream))
    using (var reader = new StreamReader(stream))
    using (var csv = new CsvReader(reader))
    {
        writer.WriteLine("FirstName,LastName");
        writer.WriteLine("\"Jon\"hn\"\",\"Doe\"");
        writer.WriteLine("\"Jane\",\"Doe\"");
        writer.Flush();
        stream.Position = 0;

        var good = new List<Test>();
        var bad = new List<string>();
        var isRecordBad = false;
        csv.Configuration.BadDataFound = context =>
        {
            isRecordBad = true;
            bad.Add(context.RawRecord);
        };
        while (csv.Read())
        {
            var record = csv.GetRecord<Test>();
            if (!isRecordBad)
            {
                good.Add(record);
            }

            isRecordBad = false;
        }

        good.Dump();
        bad.Dump();
    }
}

public class Test
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

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