使用CsvHelper将所有值从CSV读入列表 [英] Read all values from CSV into a List using CsvHelper

问题描述

所以我一直在读，我不应该写我自己的CSV读写器，所以我一直在试图使用通过nuget安装的CsvHelper库。 CSV文件是灰度图像，行数为图像高度，数字列为宽度。我想把这些值逐行读到单个 List< string> 或 List< byte> / p>

我到目前为止的代码是：

 使用CsvHelper; 
 
 public static List< string> ReadInCSV（string absolutePath）
 {
 IEnumerable< string> allValues; 
 
使用（TextReader fileReader = File.OpenText（absolutePath））
 {
 var csv = new CsvReader（fileReader）; 
 csv.Configuration.HasHeaderRecord = false; 
 allValues = csv.GetRecords< string> 
} 
 
 return allValues.ToList< string>（）; 
} 
  

但 allValues.ToList< string> / code> is throwing a：

CsvConfigurationException未由用户代码处理

CsvHelper.dll中发生类型为CsvHelper.Configuration.CsvConfigurationException的异常，但未在用户代码中处理

>附加信息：继承IEnumerable的类型不能自动映射。你不小心调用了GetRecord或WriteRecord，而不是调用GetRecords或WriteRecords对记录列表进行操作。

GetRecords 可能期待我自己的自定义类，但我只是想要的值作为一些原始类型或字符串。此外，我怀疑整个行被转换为单个字符串，而不是每个值都是单独的字符串。

解决方案

to @Marc L's post you can try this：

  public static List< string& ReadInCSV（string absolutePath）{
 List< string> result = new List< string>（）; 
 string value; 
 using（TextReader fileReader = File.OpenText（absolutePath））{
 var csv = new CsvReader（fileReader）; 
 csv.Configuration.HasHeaderRecord = false; 
 while（csv.Read（））{
 for（int i = 0; csv.TryGetField< string>（i，out value）; i ++）{
 result.Add（value） ; 
} 
} 
} 
返回结果; 
} 
  

So I've been reading that I shouldn't write my own CSV reader/writer, so I've been trying to use the CsvHelper library installed via nuget. The CSV file is a grey scale image, with the number of rows being the image height and the number columns the width. I would like to read the values row-wise into a single List<string> or List<byte>.

The code I have so far is:

using CsvHelper;

public static List<string> ReadInCSV(string absolutePath)
{
    IEnumerable<string> allValues;

    using (TextReader fileReader = File.OpenText(absolutePath))
    {
        var csv = new CsvReader(fileReader);
        csv.Configuration.HasHeaderRecord = false;
        allValues = csv.GetRecords<string>
    }

    return allValues.ToList<string>();
}

But allValues.ToList<string>() is throwing a:

CsvConfigurationException was unhandled by user code

An exception of type 'CsvHelper.Configuration.CsvConfigurationException' occurred in CsvHelper.dll but was not handled in user code

Additional information: Types that inherit IEnumerable cannot be auto mapped. Did you accidentally call GetRecord or WriteRecord which acts on a single record instead of calling GetRecords or WriteRecords which acts on a list of records?

GetRecords is probably expecting my own custom class, but I'm just wanting the values as some primitive type or string. Also, I suspect the entire row is being converted to a single string, instead of each value being a separate string.

解决方案

According to @Marc L's post you can try this:

public static List<string> ReadInCSV(string absolutePath) {
    List<string> result = new List<string>();
    string value;
    using (TextReader fileReader = File.OpenText(absolutePath)) {
        var csv = new CsvReader(fileReader);
        csv.Configuration.HasHeaderRecord = false;
        while (csv.Read()) {
           for(int i=0; csv.TryGetField<string>(i, out value); i++) {
                result.Add(value);
            }
        }
    }
    return result;
}

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