如何将CSV文件读入.NET Datatable

Question

如何将CSV文件加载到System.Data.DataTable，根据CSV文件创建数据表？

常规的ADO.net功能是否允许这样做？

Answer 1

我一直在使用OleDb提供商。但是，如果您正在读取具有数值但是希望将它们视为文本的行，则会出现问题。但是，您可以通过创建schema.ini文件来解决该问题。这是我使用的方法：

// using System.Data;
// using System.Data.OleDb;
// using System.Globalization;
// using System.IO;

static DataTable GetDataTableFromCsv(string path, bool isFirstRowHeader)
{
    string header = isFirstRowHeader ? "Yes" : "No";

    string pathOnly = Path.GetDirectoryName(path);
    string fileName = Path.GetFileName(path);

    string sql = @"SELECT * FROM [" + fileName + "]";

    using(OleDbConnection connection = new OleDbConnection(
              @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + pathOnly + 
              ";Extended Properties=\"Text;HDR=" + header + "\""))
    using(OleDbCommand command = new OleDbCommand(sql, connection))
    using(OleDbDataAdapter adapter = new OleDbDataAdapter(command))
    {
        DataTable dataTable = new DataTable();
        dataTable.Locale = CultureInfo.CurrentCulture;
        adapter.Fill(dataTable);
        return dataTable;
    }
}

Answer 2

这是一个优秀的类，它将使用数据结构将CSV数据复制到数据表中以创建DataTable：

A portable and efficient generic parser for flat files

配置简单，易于使用。我劝你看看。

Answer 3

我决定使用Sebastien Lorion's Csv Reader。

Jay Riggs的建议也是一个很好的解决方案，但我并不需要Andrew Rissing's Generic Parser 提供的所有功能。

更新10/25/2010

在我的项目中使用Sebastien Lorion's Csv Reader近一年半之后，我发现在解析一些我认为格式正确的csv文件时会抛出异常。

所以，我确实切换到Andrew Rissing's Generic Parser ，似乎做得更好。

更新2014年9月22日

现在，我主要使用此扩展方法来读取分隔文本：

https://github.com/Core-Techs/Common/blob/master/CoreTechs.Common/Text/DelimitedTextExtensions.cs#L22

https://www.nuget.org/packages/CoreTechs.Common/

2015年2月20日更新

示例：

var csv = @"Name, Age
Ronnie, 30
Mark, 40
Ace, 50";

TextReader reader = new StringReader(csv);
var table = new DataTable();
using(var it = reader.ReadCsvWithHeader().GetEnumerator())
{

    if (!it.MoveNext()) return;

    foreach (var k in it.Current.Keys)
        table.Columns.Add(k);

    do
    {
        var row = table.NewRow();
        foreach (var k in it.Current.Keys)
            row[k] = it.Current[k];

        table.Rows.Add(row);

    } while (it.MoveNext());
}

Answer 4

嘿，它的工作 100％

  public static DataTable ConvertCSVtoDataTable(string strFilePath)
  {
    DataTable dt = new DataTable();
    using (StreamReader sr = new StreamReader(strFilePath))
    {
        string[] headers = sr.ReadLine().Split(',');
        foreach (string header in headers)
        {
            dt.Columns.Add(header);
        }
        while (!sr.EndOfStream)
        {
            string[] rows = sr.ReadLine().Split(',');
            DataRow dr = dt.NewRow();
            for (int i = 0; i < headers.Length; i++)
            {
                dr[i] = rows[i];
            }
            dt.Rows.Add(dr);
        }

    }


    return dt;
   }

CSV图片

导入数据表

Answer 5

我们总是习惯使用Jet.OLEDB驱动程序，直到我们开始使用64位应用程序。微软没有也不会发布64位Jet驱动程序。这是我们提出的一个简单的解决方案，它使用File.ReadAllLines和String.Split来读取和解析CSV文件并手动加载DataTable。如上所述，它不处理其中一个列值包含逗号的情况。我们主要使用它来读取自定义配置文件 - 关于使用CSV文件的好处是我们可以在Excel中编辑它们。

string CSVFilePathName = @"C:\test.csv";
string[] Lines = File.ReadAllLines(CSVFilePathName);
string[] Fields;
Fields = Lines[0].Split(new char[] { ',' });
int Cols = Fields.GetLength(0);
DataTable dt = new DataTable();
//1st row must be column names; force lower case to ensure matching later on.
for (int i = 0; i < Cols; i++)
    dt.Columns.Add(Fields[i].ToLower(), typeof(string));
DataRow Row;
for (int i = 1; i < Lines.GetLength(0); i++)
{
    Fields = Lines[i].Split(new char[] { ',' });
    Row = dt.NewRow();
    for (int f = 0; f < Cols; f++)
        Row[f] = Fields[f];
    dt.Rows.Add(Row);
}

Answer 6

这是我使用它的代码，但您的应用必须使用net version 3.5

运行

private void txtRead_Click(object sender, EventArgs e)
        {
           // var filename = @"d:\shiptest.txt";

            openFileDialog1.InitialDirectory = "d:\\";
            openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
            DialogResult result = openFileDialog1.ShowDialog();
            if (result == DialogResult.OK)
            {
                if (openFileDialog1.FileName != "")
                {
                    var reader = ReadAsLines(openFileDialog1.FileName);

                    var data = new DataTable();

                    //this assume the first record is filled with the column names
                    var headers = reader.First().Split(',');
                    foreach (var header in headers)
                    {
                        data.Columns.Add(header);
                    }

                    var records = reader.Skip(1);
                    foreach (var record in records)
                    {
                        data.Rows.Add(record.Split(','));
                    }

                    dgList.DataSource = data;
                }
            }
        }

        static IEnumerable<string> ReadAsLines(string filename)
        {
            using (StreamReader reader = new StreamReader(filename))
                while (!reader.EndOfStream)
                    yield return reader.ReadLine();
        }

Answer 7

您可以在C＃中使用Microsoft.VisualBasic.FileIO.TextFieldParser dll来实现它。

static void Main()
        {
            string csv_file_path=@"C:\Users\Administrator\Desktop\test.csv";

            DataTable csvData = GetDataTabletFromCSVFile(csv_file_path);

            Console.WriteLine("Rows count:" + csvData.Rows.Count);

            Console.ReadLine();
        }


private static DataTable GetDataTabletFromCSVFile(string csv_file_path)
        {
            DataTable csvData = new DataTable();

            try
            {

            using(TextFieldParser csvReader = new TextFieldParser(csv_file_path))
                {
                    csvReader.SetDelimiters(new string[] { "," });
                    csvReader.HasFieldsEnclosedInQuotes = true;
                    string[] colFields = csvReader.ReadFields();
                    foreach (string column in colFields)
                    {
                        DataColumn datecolumn = new DataColumn(column);
                        datecolumn.AllowDBNull = true;
                        csvData.Columns.Add(datecolumn);
                    }

                    while (!csvReader.EndOfData)
                    {
                        string[] fieldData = csvReader.ReadFields();
                        //Making empty value as null
                        for (int i = 0; i < fieldData.Length; i++)
                        {
                            if (fieldData[i] == "")
                            {
                                fieldData[i] = null;
                            }
                        }
                        csvData.Rows.Add(fieldData);
                    }
                }
            }
            catch (Exception ex)
            {
            }
            return csvData;
        }

Answer 8

我遇到了这段代码，它使用Linq和regex来解析CSV文件。引用文章现在超过一年半，但是没有遇到过使用Linq（和正则表达式）解析CSV的更简洁的方法。需要注意的是，此处应用的正则表达式用于逗号分隔文件（将在引号内检测逗号！）并且它可能不适合标题，但有一种方法可以克服这些问题）。走高峰：

Dim lines As String() = System.IO.File.ReadAllLines(strCustomerFile)
Dim pattern As String = ",(?=(?:[^""]*""[^""]*"")*(?![^""]*""))"
Dim r As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex(pattern)
Dim custs = From line In lines _
            Let data = r.Split(line) _
                Select New With {.custnmbr = data(0), _
                                 .custname = data(1)}
For Each cust In custs
    strCUSTNMBR = Replace(cust.custnmbr, Chr(34), "")
    strCUSTNAME = Replace(cust.custname, Chr(34), "")
Next

Answer 9

我找到的最佳选项，它解决了您可能安装了不同版本的Office以及Chuck Bevitt mentioned等32/64位问题的问题，FileHelpers。

可以使用NuGet将其添加到项目引用中，它提供了一个单行解决方案：

CommonEngine.CsvToDataTable(path, "ImportRecord", ',', true);

Answer 10

对于那些不想使用外部库并且不想使用OleDB的人，请参阅下面的示例。我发现的一切都是OleDB，外部库，或者只是基于逗号分割！对于我的情况，OleDB没有工作，所以我想要一些不同的东西。

我发现MarkJ的一篇文章引用了Microsoft.VisualBasic.FileIO.TextFieldParser方法，如here所示。这篇文章是用VB编写的，不会返回数据表，所以请看下面的例子。

public static DataTable LoadCSV(string path, bool hasHeader)
    {
        DataTable dt = new DataTable();

        using (var MyReader = new Microsoft.VisualBasic.FileIO.TextFieldParser(path))
        {
            MyReader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited;
            MyReader.Delimiters = new String[] { "," };

            string[] currentRow;

            //'Loop through all of the fields in the file.  
            //'If any lines are corrupt, report an error and continue parsing.  
            bool firstRow = true;
            while (!MyReader.EndOfData)
            {
                try
                {
                    currentRow = MyReader.ReadFields();

                    //Add the header columns
                    if (hasHeader && firstRow)
                    {
                        foreach (string c in currentRow)
                        {
                            dt.Columns.Add(c, typeof(string));
                        }

                        firstRow = false;
                        continue;
                    }

                    //Create a new row
                    DataRow dr = dt.NewRow();
                    dt.Rows.Add(dr);

                    //Loop thru the current line and fill the data out
                    for(int c = 0; c < currentRow.Count(); c++)
                    {
                        dr[c] = currentRow[c];
                    }
                }
                catch (Microsoft.VisualBasic.FileIO.MalformedLineException ex)
                {
                    //Handle the exception here
                }
            }
        }

        return dt;
    }

Answer 11

修改先生 ChuckBevitt

工作解决方案：

string CSVFilePathName = APP_PATH + "Facilities.csv";
string[] Lines = File.ReadAllLines(CSVFilePathName);
string[] Fields;
Fields = Lines[0].Split(new char[] { ',' });
int Cols = Fields.GetLength(0);
DataTable dt = new DataTable();
//1st row must be column names; force lower case to ensure matching later on.
for (int i = 0; i < Cols-1; i++)
        dt.Columns.Add(Fields[i].ToLower(), typeof(string));
DataRow Row;
for (int i = 0; i < Lines.GetLength(0)-1; i++)
{
        Fields = Lines[i].Split(new char[] { ',' });
        Row = dt.NewRow();
        for (int f = 0; f < Cols-1; f++)
                Row[f] = Fields[f];
        dt.Rows.Add(Row);
}

Answer 12

非常基本的答案：如果你没有一个可以使用简单拆分功能的复杂csv，这将很适合导入（注意这个导入为字符串，如果需要，我会稍后进行数据类型转换）

 private DataTable csvToDataTable(string fileName, char splitCharacter)
    {                
        StreamReader sr = new StreamReader(fileName);
        string myStringRow = sr.ReadLine();
        var rows = myStringRow.Split(splitCharacter);
        DataTable CsvData = new DataTable();
        foreach (string column in rows)
        {
            //creates the columns of new datatable based on first row of csv
            CsvData.Columns.Add(column);
        }
        myStringRow = sr.ReadLine();
        while (myStringRow != null)
        {
            //runs until string reader returns null and adds rows to dt 
            rows = myStringRow.Split(splitCharacter);
            CsvData.Rows.Add(rows);
            myStringRow = sr.ReadLine();
        }
        sr.Close();
        sr.Dispose();
        return CsvData;
    }

我的方法，如果我导入一个带有字符串[] separater的表，并处理我正在阅读的当前行可能已经转到csv或文本文件中的下一行的问题＆lt; - IN我希望这种情况循环，直到我得到第一行（列）中的总行数

public static DataTable ImportCSV(string fullPath, string[] sepString)
    {
        DataTable dt = new DataTable();
        using (StreamReader sr = new StreamReader(fullPath))
        {
           //stream uses using statement because it implements iDisposable
            string firstLine = sr.ReadLine();
            var headers = firstLine.Split(sepString, StringSplitOptions.None);
            foreach (var header in headers)
            {
               //create column headers
                dt.Columns.Add(header);
            }
            int columnInterval = headers.Count();
            string newLine = sr.ReadLine();
            while (newLine != null)
            {
                //loop adds each row to the datatable
                var fields = newLine.Split(sepString, StringSplitOptions.None); // csv delimiter    
                var currentLength = fields.Count();
                if (currentLength < columnInterval)
                {
                    while (currentLength < columnInterval)
                    {
                       //if the count of items in the row is less than the column row go to next line until count matches column number total
                        newLine += sr.ReadLine();
                        currentLength = newLine.Split(sepString, StringSplitOptions.None).Count();
                    }
                    fields = newLine.Split(sepString, StringSplitOptions.None);
                }
                if (currentLength > columnInterval)
                {  
                    //ideally never executes - but if csv row has too many separators, line is skipped
                    newLine = sr.ReadLine();
                    continue;
                }
                dt.Rows.Add(fields);
                newLine = sr.ReadLine();
            }
            sr.Close();
        }

        return dt;
    }

Answer 13

这是一个使用ADO.Net的ODBC文本驱动程序的解决方案：

Dim csvFileFolder As String = "C:\YourFileFolder"
Dim csvFileName As String = "YourFile.csv"

'Note that the folder is specified in the connection string,
'not the file. That's specified in the SELECT query, later.
Dim connString As String = "Driver={Microsoft Text Driver (*.txt; *.csv)};Dbq=" _
    & csvFileFolder & ";Extended Properties=""Text;HDR=No;FMT=Delimited"""
Dim conn As New Odbc.OdbcConnection(connString)

'Open a data adapter, specifying the file name to load
Dim da As New Odbc.OdbcDataAdapter("SELECT * FROM [" & csvFileName & "]", conn)
'Then fill a data table, which can be bound to a grid
Dim dt As New DataTableda.Fill(dt)

grdCSVData.DataSource = dt

填充后，您可以对数据表的属性（如ColumnName）进行赋值，以充分利用ADO.Net数据对象的所有功能。

在VS2008中，你可以使用Linq来达到同样的效果。

注意：这可能与this SO问题重复。

Answer 14

    private static DataTable LoadCsvData(string refPath)
    {
        var cfg = new Configuration() { Delimiter = ",", HasHeaderRecord = true };
        var result = new DataTable();
        using (var sr = new StreamReader(refPath, Encoding.UTF8, false, 16384 * 2))
        {
            using (var rdr = new CsvReader(sr, cfg))
            using (var dataRdr = new CsvDataReader(rdr))
            {
                result.Load(dataRdr);
            }
        }
        return result;
    }

使用：https://joshclose.github.io/CsvHelper/

Answer 15

使用Cinchoo ETL-一个开放源代码库，您只需几行代码即可轻松将CSV文件转换为DataTable。

using (var p = new ChoCSVReader(** YOUR CSV FILE **)
     .WithFirstLineHeader()
    )
{
    var dt = p.AsDataTable();
}

有关更多信息，请访问codeproject文章。

希望有帮助。

Answer 16

无法阻止我加入自己的旋转。这比我过去使用的更好，更紧凑。

此解决方案：

• 不依赖于数据库驱动程序或第三方库。
• 重复列名称不会失败
• 处理数据中的逗号
• 处理任何分隔符，而不仅仅是逗号（尽管这是默认设置）

这是我想出的：

  Public Function ToDataTable(FileName As String, Optional Delimiter As String = ",") As DataTable
    ToDataTable = New DataTable
    Using TextFieldParser As New Microsoft.VisualBasic.FileIO.TextFieldParser(FileName) With
      {.HasFieldsEnclosedInQuotes = True, .TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited, .TrimWhiteSpace = True}
      With TextFieldParser
        .SetDelimiters({Delimiter})
        .ReadFields.ToList.Unique.ForEach(Sub(x) ToDataTable.Columns.Add(x))
        ToDataTable.Columns.Cast(Of DataColumn).ToList.ForEach(Sub(x) x.AllowDBNull = True)
        Do Until .EndOfData
          ToDataTable.Rows.Add(.ReadFields.Select(Function(x) Text.BlankToNothing(x)).ToArray)
        Loop
      End With
    End Using
  End Function

这取决于扩展方法（Unique）来处理在How to append unique numbers to a list of strings

中找到的重复列名称作为我的答案

这里是BlankToNothing辅助函数：

  Public Function BlankToNothing(ByVal Value As String) As Object 
    If String.IsNullOrEmpty(Value) Then Return Nothing
    Return Value
  End Function

Answer 17

public class Csv
{
    public static DataTable DataSetGet(string filename, string separatorChar, out List<string> errors)
    {
        errors = new List<string>();
        var table = new DataTable("StringLocalization");
        using (var sr = new StreamReader(filename, Encoding.Default))
        {
            string line;
            var i = 0;
            while (sr.Peek() >= 0)
            {
                try
                {
                    line = sr.ReadLine();
                    if (string.IsNullOrEmpty(line)) continue;
                    var values = line.Split(new[] {separatorChar}, StringSplitOptions.None);
                    var row = table.NewRow();
                    for (var colNum = 0; colNum < values.Length; colNum++)
                    {
                        var value = values[colNum];
                        if (i == 0)
                        {
                            table.Columns.Add(value, typeof (String));
                        }
                        else
                        {
                            row[table.Columns[colNum]] = value;
                        }
                    }
                    if (i != 0) table.Rows.Add(row);
                }
                catch(Exception ex)
                {
                    errors.Add(ex.Message);
                }
                i++;
            }
        }
        return table;
    }
}

Answer 18

使用此功能，一个函数可以解决所有逗号和引号的问题：

public static DataTable CsvToDataTable(string strFilePath)
    {

        if (File.Exists(strFilePath))
        {

            string[] Lines;
            string CSVFilePathName = strFilePath;

            Lines = File.ReadAllLines(CSVFilePathName);
            while (Lines[0].EndsWith(","))
            {
                Lines[0] = Lines[0].Remove(Lines[0].Length - 1);
            }
            string[] Fields;
            Fields = Lines[0].Split(new char[] { ',' });
            int Cols = Fields.GetLength(0);
            DataTable dt = new DataTable();
            //1st row must be column names; force lower case to ensure matching later on.
            for (int i = 0; i < Cols; i++)
                dt.Columns.Add(Fields[i], typeof(string));
            DataRow Row;
            int rowcount = 0;
            try
            {
                string[] ToBeContinued = new string[]{};
                bool lineToBeContinued = false;
                for (int i = 1; i < Lines.GetLength(0); i++)
                {
                    if (!Lines[i].Equals(""))
                    {
                        Fields = Lines[i].Split(new char[] { ',' });
                        string temp0 = string.Join("", Fields).Replace("\"\"", "");
                        int quaotCount0 = temp0.Count(c => c == '"');
                        if (Fields.GetLength(0) < Cols || lineToBeContinued || quaotCount0 % 2 != 0)
                        {
                            if (ToBeContinued.GetLength(0) > 0)
                            {
                                ToBeContinued[ToBeContinued.Length - 1] += "\n" + Fields[0];
                                Fields = Fields.Skip(1).ToArray();
                            }
                            string[] newArray = new string[ToBeContinued.Length + Fields.Length];
                            Array.Copy(ToBeContinued, newArray, ToBeContinued.Length);
                            Array.Copy(Fields, 0, newArray, ToBeContinued.Length, Fields.Length);
                            ToBeContinued = newArray;
                            string temp = string.Join("", ToBeContinued).Replace("\"\"", "");
                            int quaotCount = temp.Count(c => c == '"');
                            if (ToBeContinued.GetLength(0) >= Cols && quaotCount % 2 == 0 )
                            {
                                Fields = ToBeContinued;
                                ToBeContinued = new string[] { };
                                lineToBeContinued = false;
                            }
                            else
                            {
                                lineToBeContinued = true;
                                continue;
                            }
                        }

                        //modified by Teemo @2016 09 13
                        //handle ',' and '"'
                        //Deserialize CSV following Excel's rule:
                        // 1: If there is commas in a field, quote the field.
                        // 2: Two consecutive quotes indicate a user's quote.

                        List<int> singleLeftquota = new List<int>();
                        List<int> singleRightquota = new List<int>();

                        //combine fileds if number of commas match
                        if (Fields.GetLength(0) > Cols) 
                        {
                            bool lastSingleQuoteIsLeft = true;
                            for (int j = 0; j < Fields.GetLength(0); j++)
                            {
                                bool leftOddquota = false;
                                bool rightOddquota = false;
                                if (Fields[j].StartsWith("\"")) 
                                {
                                    int numberOfConsecutiveQuotes = 0;
                                    foreach (char c in Fields[j]) //start with how many "
                                    {
                                        if (c == '"')
                                        {
                                            numberOfConsecutiveQuotes++;
                                        }
                                        else
                                        {
                                            break;
                                        }
                                    }
                                    if (numberOfConsecutiveQuotes % 2 == 1)//start with odd number of quotes indicate system quote
                                    {
                                        leftOddquota = true;
                                    }
                                }

                                if (Fields[j].EndsWith("\""))
                                {
                                    int numberOfConsecutiveQuotes = 0;
                                    for (int jj = Fields[j].Length - 1; jj >= 0; jj--)
                                    {
                                        if (Fields[j].Substring(jj,1) == "\"") // end with how many "
                                        {
                                            numberOfConsecutiveQuotes++;
                                        }
                                        else
                                        {
                                            break;
                                        }
                                    }

                                    if (numberOfConsecutiveQuotes % 2 == 1)//end with odd number of quotes indicate system quote
                                    {
                                        rightOddquota = true;
                                    }
                                }
                                if (leftOddquota && !rightOddquota)
                                {
                                    singleLeftquota.Add(j);
                                    lastSingleQuoteIsLeft = true;
                                }
                                else if (!leftOddquota && rightOddquota)
                                {
                                    singleRightquota.Add(j);
                                    lastSingleQuoteIsLeft = false;
                                }
                                else if (Fields[j] == "\"") //only one quota in a field
                                {
                                    if (lastSingleQuoteIsLeft)
                                    {
                                        singleRightquota.Add(j);
                                    }
                                    else
                                    {
                                        singleLeftquota.Add(j);
                                    }
                                }
                            }
                            if (singleLeftquota.Count == singleRightquota.Count)
                            {
                                int insideCommas = 0;
                                for (int indexN = 0; indexN < singleLeftquota.Count; indexN++)
                                {
                                    insideCommas += singleRightquota[indexN] - singleLeftquota[indexN];
                                }
                                if (Fields.GetLength(0) - Cols >= insideCommas) //probabaly matched
                                {
                                    int validFildsCount = insideCommas + Cols; //(Fields.GetLength(0) - insideCommas) may be exceed the Cols
                                    String[] temp = new String[validFildsCount];
                                    int totalOffSet = 0;
                                    for (int iii = 0; iii < validFildsCount - totalOffSet; iii++)
                                    {
                                        bool combine = false;
                                        int storedIndex = 0;
                                        for (int iInLeft = 0; iInLeft < singleLeftquota.Count; iInLeft++)
                                        {
                                            if (iii + totalOffSet == singleLeftquota[iInLeft])
                                            {
                                                combine = true;
                                                storedIndex = iInLeft;
                                                break;
                                            }
                                        }
                                        if (combine)
                                        {
                                            int offset = singleRightquota[storedIndex] - singleLeftquota[storedIndex];
                                            for (int combineI = 0; combineI <= offset; combineI++)
                                            {
                                                temp[iii] += Fields[iii + totalOffSet + combineI] + ",";
                                            }
                                            temp[iii] = temp[iii].Remove(temp[iii].Length - 1, 1);
                                            totalOffSet += offset;
                                        }
                                        else
                                        {
                                            temp[iii] = Fields[iii + totalOffSet];
                                        }
                                    }
                                    Fields = temp;
                                }
                            }
                        }
                        Row = dt.NewRow();
                        for (int f = 0; f < Cols; f++)
                        {
                            Fields[f] = Fields[f].Replace("\"\"", "\""); //Two consecutive quotes indicate a user's quote
                            if (Fields[f].StartsWith("\""))
                            {
                                if (Fields[f].EndsWith("\""))
                                {
                                    Fields[f] = Fields[f].Remove(0, 1);
                                    if (Fields[f].Length > 0)
                                    {
                                        Fields[f] = Fields[f].Remove(Fields[f].Length - 1, 1);
                                    }
                                }
                            }
                            Row[f] = Fields[f];
                        }
                        dt.Rows.Add(Row);
                        rowcount++;
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception( "row: " + (rowcount+2) + ", " + ex.Message);
            }
            //OleDbConnection connection = new OleDbConnection(string.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0}; Extended Properties=""text;HDR=Yes;FMT=Delimited"";", FilePath + FileName));
            //OleDbCommand command = new OleDbCommand("SELECT * FROM " + FileName, connection);
            //OleDbDataAdapter adapter = new OleDbDataAdapter(command);
            //DataTable dt = new DataTable();
            //adapter.Fill(dt);
            //adapter.Dispose();
            return dt;
        }
        else
            return null;

        //OleDbConnection connection = new OleDbConnection(string.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0}; Extended Properties=""text;HDR=Yes;FMT=Delimited"";", strFilePath));
        //OleDbCommand command = new OleDbCommand("SELECT * FROM " + strFileName, connection);
        //OleDbDataAdapter adapter = new OleDbDataAdapter(command);
        //DataTable dt = new DataTable();
        //adapter.Fill(dt);
        //return dt;
    }

Answer 19

只需共享这种扩展方法，我希望它可以对某人有所帮助。

public static List<string> ToCSV(this DataSet ds, char separator = '|')
{
    List<string> lResult = new List<string>();

    foreach (DataTable dt in ds.Tables)
    {
        StringBuilder sb = new StringBuilder();
        IEnumerable<string> columnNames = dt.Columns.Cast<DataColumn>().
                                          Select(column => column.ColumnName);
        sb.AppendLine(string.Join(separator.ToString(), columnNames));

        foreach (DataRow row in dt.Rows)
        {
            IEnumerable<string> fields = row.ItemArray.Select(field =>
              string.Concat("\"", field.ToString().Replace("\"", "\"\""), "\""));
            sb.AppendLine(string.Join(separator.ToString(), fields));
        }

        lResult.Add(sb.ToString());
    }
    return lResult;
}

public static DataSet CSVtoDataSet(this List<string> collectionCSV, char separator = '|')
{
    var ds = new DataSet();

    foreach (var csv in collectionCSV)
    {
        var dt = new DataTable();

        var readHeader = false;
        foreach (var line in csv.Split(new[] { Environment.NewLine }, StringSplitOptions.None))
        {
            if (!readHeader)
            {
                foreach (var c in line.Split(separator))
                    dt.Columns.Add(c);
            }
            else
            {
                dt.Rows.Add(line.Split(separator));
            }
        }

        ds.Tables.Add(dt);
    }

    return ds;
}

Answer 20

 Public Function ReadCsvFileToDataTable(strFilePath As String) As DataTable
    Dim dtCsv As DataTable = New DataTable()
    Dim Fulltext As String
    Using sr As StreamReader = New StreamReader(strFilePath)
        While Not sr.EndOfStream
            Fulltext = sr.ReadToEnd().ToString()
            Dim rows As String() = Fulltext.Split(vbLf)
            For i As Integer = 0 To rows.Count() - 1 - 1
                Dim rowValues As String() = rows(i).Split(","c)
                If True Then
                    If i = 0 Then
                        For j As Integer = 0 To rowValues.Count() - 1
                            dtCsv.Columns.Add(rowValues(j))
                        Next
                    Else
                        Dim dr As DataRow = dtCsv.NewRow()
                        For k As Integer = 0 To rowValues.Count() - 1
                            dr(k) = rowValues(k).ToString()
                        Next
                        dtCsv.Rows.Add(dr)
                    End If
                End If
            Next
        End While
    End Using
    Return dtCsv
End Function

Answer 21

我使用一个名为ExcelDataReader的库，您可以在Nuget上找到它

我将所有内容封装在一个函数中，您可以直接将其复制到代码中 给它一个csv文件的路径，为您提供一个表的数据集

     public static DataSet GetDataSet(string filepath)
    {


        var stream = File.OpenRead(filepath);

        try
        {

            var reader = ExcelReaderFactory.CreateCsvReader(stream, new ExcelReaderConfiguration()
            {
                LeaveOpen = false


            });

            var result = reader.AsDataSet(new ExcelDataSetConfiguration()
            {
                // Gets or sets a value indicating whether to set the DataColumn.DataType 
                // property in a second pass.
                UseColumnDataType = true,

                // Gets or sets a callback to determine whether to include the current sheet
                // in the DataSet. Called once per sheet before ConfigureDataTable.
                FilterSheet = (tableReader, sheetIndex) => true,

                // Gets or sets a callback to obtain configuration options for a DataTable. 
                ConfigureDataTable = (tableReader) => new ExcelDataTableConfiguration()
                {
                    // Gets or sets a value indicating the prefix of generated column names.
                    EmptyColumnNamePrefix = "Column",

                    // Gets or sets a value indicating whether to use a row from the 
                    // data as column names.
                    UseHeaderRow = true,



                    // Gets or sets a callback to determine which row is the header row. 
                    // Only called when UseHeaderRow = true.
                    ReadHeaderRow = (rowReader) =>
                    {
                        // F.ex skip the first row and use the 2nd row as column headers:
                        //rowReader.Read();
                    },

                    // Gets or sets a callback to determine whether to include the 
                    // current row in the DataTable.
                    FilterRow = (rowReader) =>
                    {
                        return true;
                    },

                    // Gets or sets a callback to determine whether to include the specific
                    // column in the DataTable. Called once per column after reading the 
                    // headers.
                    FilterColumn = (rowReader, columnIndex) =>
                    {
                        return true;
                    }
                }
            });

            return result;

        }
        catch (Exception ex)
        {

            return null;

        }
        finally
        {

            stream.Close();
            stream.Dispose();
        }

    }   

Answer 22

我最近为.NET编写了CSV parser的I'm claiming is currently the fastest，可作为一个nuget包使用：Sylvan.Data.Csv。

使用该库加载DataTable非常简单。

using var dr = CsvDataReader.Create("data.csv");
var dt = new DataTable();
dt.Load(dr);

假设您的文件是带有标题的标准逗号分隔文件，这就是您所需要的。还有一些选项允许读取没有标题的文件，并使用其他定界符等。

还可以为CSV文件提供自定义架构，以便可以将列视为string值以外的值。这样将使DataTable列中加载的值更易于使用，因为在访问它们时不必强制它们。

这可以通过提供ICsvSchemaProvider实现来实现，该实现公开单个方法DbColumn? GetColumn(string? name, int ordinal)。 DbColumn类型是在System.Data.Common中定义的抽象类型，这意味着如果您实现自己的模式提供程序，则也必须提供该实现。 DbColumn类型公开有关列的各种元数据，并且您可以选择根据需要公开尽可能多的元数据。最重要的元数据是DataType，它用于

一个非常简单的实现，它可以公开类型信息，如下所示：

class TypedCsvColumn : DbColumn
{
    public TypedCsvColumn(Type type, bool allowNull)
    {
        // if you assign ColumnName here, it will override whatever is in the csv header
        this.DataType = type;
        this.AllowDBNull = allowNull;
    }
}
    
class TypedCsvSchema : ICsvSchemaProvider
{
    List<TypedCsvColumn> columns;

    public TypedCsvSchema()
    {
        this.columns = new List<TypedCsvColumn>();
    }

    public TypedCsvSchema Add(Type type, bool allowNull = false)
    {
        this.columns.Add(new TypedCsvColumn(type, allowNull));
        return this;
    }

    DbColumn? ICsvSchemaProvider.GetColumn(string? name, int ordinal)
    {
        return ordinal < columns.Count ? columns[ordinal] : null;
    }
}

要使用此实现，请执行以下操作：

var schema = new TypedCsvSchema()
    .Add(typeof(int))
    .Add(typeof(string))
    .Add(typeof(double), true)
    .Add(typeof(DateTime))
    .Add(typeof(DateTime), true);
var options = new CsvDataReaderOptions
{
    Schema = schema
};


using var dr = CsvDataReader.Create("data.csv", options);
...