如何处理使用 CsvHelper 解析时的空列？

Question

我有一个 CSV 文件，我正在尝试解析它，但是在 int 数据类型 column.In 文件上出现以下错误，我为此列传递了空白或空值。

[AutoMap(typeof(Test))]
[FileEntity("Test")]
public class TestFileEntity : BaseFileEntity
{
    [CsvFileColumn(1)]
    public int TestId { get; set; }
}

public IEnumerable<BaseFileEntity> Parse(Stream masterData, Type entityType, out IEnumerable<MasterDataFileParserError> errors)
{
    var list = new List<BaseFileEntity>();
    var errorList = new List<MasterDataFileParserError>();

    try
    {
        using (var reader = new StreamReader(masterData))
        {
            var parser = new CsvReader(reader, new CsvHelper.Configuration.Configuration
            {
                HasHeaderRecord = true,
                HeaderValidated = null,
                MissingFieldFound = null
            });

            list.AddRange(parser.GetRecords(entityType).Cast<BaseFileEntity>());
        }
    }
    catch (Exception ex)
    {
        if (ex.Data == null || ex.Data.Count == 0)
        {
            errorList.Add(new MasterDataFileParserError
            {
                Error = ex.Message,
                Description = ex.ToString()
            });
        }
        else
        {
            foreach (var key in ex.Data.Keys)
            {
                errorList.Add(new MasterDataFileParserError
                {
                    Error = ex.Message,
                    Description = $"{key}: {ex.Data[key]}"
                });
            }
        }
    }

    errors = errorList;

    return list;
}

此行异常：list.AddRange(parser.GetRecords(entityType).Cast<BaseFileEntity>());

错误：

An error has occurred while parsing 'xyz.csv' file for 'Test' entity: '[{"Error":"The conversion cannot be performed.\r\n Text: ''\r\n
MemberType: System.Int32\r\n TypeConverter: 'CsvHelper.TypeConversion.Int32Converter'","Description":"CsvHelper.TypeConversion.TypeConverterException: The conversion cannot be performed.\r\n Text: ''\r\n MemberType: System.Int32\r\n TypeConverter: 'CsvHelper.TypeConversion.Int32Converter'\r\n at CsvHelper.Configuration.Configuration.<>c.<.ctor>b__148_4(CsvHelperException exception)\r\n at CsvHelper.CsvReader.d__65.MoveNext()\r\n at System.Linq.Enumerable.d__341.MoveNext()\r\n at System.Collections.Generic.List1.AddEnumerable(IEnumerable1 enumerable)\r\n at System.Collections.Generic.List1.InsertRange(Int32 index, IEnumerable1 collection)\r\n at Nec.Stanchion.Business.MasterDataFiles.Handling.MasterDataFileParser.Parse(Stream masterData, Type entityType, IEnumerable1& errors) in xyz.cs file"}]'.

原因很清楚，空白或空字符串与 int 数据类型不兼容，因此必须有一些方法允许空值或空值与 int 数据类型列值。

CsvHelper 版本=6.0.0.0

Answer 1

我在当前项目中使用的是 CsvHelper 6.1.0，刚刚测试了一个与您类似的用例，csv 文件中的 int 字段为空白，没有问题。这是我正在使用的代码，希望对您有所帮助：

        CsvReader csv = new CsvReader(new StreamReader(file.OpenReadStream()));
        csv.Configuration.RegisterClassMap<PessoaCSVMap>();
        csv.Configuration.Delimiter = ";";
        csv.Configuration.HeaderValidated = null;
        csv.Configuration.MissingFieldFound = null;
        List<Pessoas> pessoas = csv.GetRecords<Pessoas>().ToList();

public sealed class PessoaCSVMap : ClassMap<Pessoas>
{
    public PessoaCSVMap()
    {
        Map(m => m.Nome).Name("Nome", "Name");
        ... etc
    }
}

Answer 2

我也有这个问题，空值/其他有问题的值在 double 或 decimal 对象中不被排除

我找到的最佳解决方案是这样的：

   //first inject the class map
   CsvReader csv = new CsvReader(new 
   StreamReader(file.OpenReadStream()));
   csv.Configuration.RegisterClassMap<SomeEntityClassMap>();
   var records = csv.GetRecords<SomeEntity>().ToList();
 
public class SomeEntityClassMap : ClassMap<SomeEntity>
{
    public SomeEntityClassMap()
    {
        //use the converter on double or decimal types
        Map(x => x.Price).TypeConverter<DoubleConverter>();
        Map(x => x.Cost).TypeConverter<DoubleConverter>();
    }
}

public class DoubleConverter : DefaultTypeConverter
{
    public override object ConvertFromString(string text, IReaderRow row, MemberMapData memberMapData)
    {
        if(double.TryParse(text, out var result))
            return result;

        return 0;
    }
}

如何处理使用 CsvHelper 解析时的空列？

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c#

csvhelper