I am trying to insert data from a .csv file into my database, but anytime I upload data, the record is empty.

This is my code so far:

[HttpPost]
public async Task<IActionResult> ImportFromExcel(IFormFile formFile)
{
    var data = new MemoryStream();
    await formFile.CopyToAsync(data);

    data.Position = 0;
    TextReader reader = new StreamReader(data);

    var csvReader = new CsvReader(reader, new CsvConfiguration(System.Globalization.CultureInfo.CurrentCulture)
                        {
                            HasHeaderRecord = true,
                            HeaderValidated = null,
                            MissingFieldFound = null
                        });

    var Name = csvReader.GetField(0).ToString();
    var dep = "cccccccccc";
    var pos = "bbbbbbbbbbb";

    await dcx.Participants.AddAsync(new Participant
                                        {
                                            Name = Name,
                                            Position = pos,
                                            Department = dep,
                                        });
    dcx.SaveChanges();
    
    return ViewComponent("ViewParticipants");
}

This is the sample data in my database table:

CodePudding user response：

In my opinion, you should call csvReader.Read() to read the file row first.

You can refer to the following test code, it works fine.

[HttpPost]
public async Task<IActionResult> ImportFromExcel(IFormFile formFile)
{
     var data = new MemoryStream();
     await formFile.CopyToAsync(data);

     data.Position = 0;
     using (var reader = new StreamReader(data))
     {
           var bad = new List<string>();
           var conf = new CsvConfiguration(CultureInfo.InvariantCulture)
           {
                HasHeaderRecord = true,
                HeaderValidated = null,
                MissingFieldFound = null,
                BadDataFound = context =>
                {
                     bad.Add(context.RawRecord);
                }
           };
           using (var csvReader = new CsvReader(reader, conf))
           {
                while (csvReader.Read())
                {
                     var Name = csvReader.GetField(0).ToString();
                     var pos = csvReader.GetField(1).ToString();
                     var dep = csvReader.GetField(2).ToString();
                        
                     await dcx.Participants.AddAsync(new Participant
                     {
                          Name = Name,
                          Position = pos,
                          Department = dep,
                     });
                     dcx.SaveChanges();
                }
           }
     }
     return ViewComponent("ViewParticipants");
}

Test Result:

CodePudding user response：

As long as the headers of your CSV match up to the names of the columns in your database, you should be able to do something like this. If the names don't match, you can use .Name("CsvColumnName") in ParticipantMap to add the name of the column in the CSV file. Example: Map(r => r.Description).Name("MyCsvDescription");.

[HttpPost]
public async Task<IActionResult> ImportFromExcel(IFormFile formFile)
{
    var data = new MemoryStream();
    await formFile.CopyToAsync(data);

    data.Position = 0;

    var conf = new CsvConfiguration(CultureInfo.InvariantCulture)
    {
         HasHeaderRecord = true,
         HeaderValidated = null,
         MissingFieldFound = null,
         BadDataFound = context =>
         {
              bad.Add(context.RawRecord);
         }
    };
    using (TextReader reader = new StreamReader(data))
    using (var csvReader = new CsvReader(reader, config)) {

        csvReader.Context.RegisterClassMap<ParticipantMap>();
        var records = csvReader.GetRecords<Participant>().ToList();

        var dep = "cccccccccc";
        var pos = "bbbbbbbbbbb";

        records.ForEach(r =>
        {
            r.Department = dep;
            r.Position = pos;
        });

        await dcx.Participants.AddRangeAsync(records);
        dcx.SaveChanges();
    }
    
    return ViewComponent("ViewParticipants");
}

public class ParticipantMap : ClassMap<Participant>
{
    public ParticipantMap()
    {
        AutoMap(CultureInfo.InvariantCulture);
        Map(r => r.Department).Ignore();
        Map(r => r.Position).Ignore();
    }
}