I would like to read the contents of a CSV file and create a dataset. I am trying like this:
var lines = File.ReadAllLines("test.csv").Select(a => a.Split(';'));
DataSet ds = new DataSet();
ds.load(lines);
but apparently this is not correct.
问问题
72945 次
6 回答
19
您需要添加引用Microsoft.VisualBasic.dll才能使用 TextFieldParser 类。
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;
}
}
有关更多信息，请参阅本文：http ://www.morgantechspace.com/2013/08/how-to-read-data-from-csv-file-in-c.html
于 2013-10-28T15:34:44.917 回答
18
您需要SELECT针对 CSV 文件运行语句来填充数据集：
编辑：这是来自http://carllbrown.blogspot.co.uk/2007/09/populate-dataset-from-csv-delimited_18.html的一些示例代码
string FileName = ...
OleDbConnection conn = new OleDbConnection
("Provider=Microsoft.Jet.OleDb.4.0; Data Source = " +
Path.GetDirectoryName(FileName) +
"; Extended Properties = \"Text;HDR=YES;FMT=Delimited\"");
conn.Open();
OleDbDataAdapter adapter = new OleDbDataAdapter
("SELECT * FROM " + Path.GetFileName(FileName), conn);
DataSet ds = new DataSet("Temp");
adapter.Fill(ds);
conn.Close();
于 2013-05-17T10:29:11.693 回答
4
然后你可以使用像Fast CSV Reader这样的库
using System.IO;
using LumenWorks.Framework.IO.Csv;
void ReadCsv()
{
// open the file "data.csv" which is a CSV file with headers
using (CsvReader csv = new CsvReader(
new StreamReader("data.csv"), true))
{
myDataRepeater.DataSource = csv;
myDataRepeater.DataBind();
}
}
于 2013-05-17T10:34:21.040 回答
1
此代码中解决的逗号 (,) 问题
即使在单元格之间添加逗号（，）也有效
读取 CSV 文件代码：
public MainWindow()
{
InitializeComponent();
DataTable dtDataSource = new DataTable();
string[] fileContent = File.ReadAllLines(@"..\\Book1.csv");
if (fileContent.Count() > 0)
{
//Create data table columns dynamically
string[] columns = fileContent[0].Split(',');
for (int i = 0; i < columns.Count(); i++)
{
dtDataSource.Columns.Add(columns[i]);
}
//Add row data dynamically
for (int i = 1; i < fileContent.Count(); i++)
{
string[] rowData = fileContent[i].Split(',');
string[] realRowData = new string[columns.Count()];
StringBuilder collaboration = new StringBuilder();
int v = 0;
//this region solves the problem of a cell containing ",".
#region CommaSepProblem
for (int j = 0, K = 0; j < rowData.Count(); j++, K++)
{
if ((rowData[j].Count(x => x == '"') % 2 == 0))//checks if the string contains even number of DoubleQuotes
{
realRowData[K] = quotesLogic((rowData[j]));
}
else if ((rowData[j].Count(x => x == '"') % 2 != 0))//If Number of DoubleQuotes are ODD
{
int c = rowData[j].Count(x => x == '"');
v = j;
while (c % 2 != 0)//Go through all the next array cell till it makes EVEN Number of DoubleQuotes.
{
collaboration.Append(rowData[j] + ",");
j++;
c += rowData[j].Count(x => x == '"');
}
collaboration.Append(rowData[j]);
realRowData[K] = quotesLogic(collaboration.ToString());
}
else { continue; }
}
#endregion
dtDataSource.Rows.Add(realRowData);
}
if (dtDataSource != null)
{
//dataGridView1 = new DataGridView();
dataGrid1.ItemsSource = dtDataSource.DefaultView;
}
}
}
方法需要添加：
string quotesLogic(string collaboration)
{
StringBuilder after = new StringBuilder(collaboration);
if (after.ToString().StartsWith("\"") && after.ToString().EndsWith("\""))//removes 1st and last quotes as those are system generated
{
after.Remove(0, 1);
after.Remove(after.Length - 1, 1);
int count = after.Length - 1;
//FACT: if you try to add DoubleQuote in a cell in excel. It'll save that quote as 2 times DoubleQuote(Like "") which means first DoubleQuote is to give instruction to CPU that the next DoubleQuote is not system generated.
while (count > 0)//This loop find twice insertion of 2 DoubleQuotes and neutralise them to One DoubleQuote.
{
if (after[count] == '"' && after[count - 1] == '"')
{
after.Remove(count, 1);
}
count--;
}
}
return after.ToString();
}
于 2016-09-29T12:39:26.107 回答
0
我在下面编写了五种方法，它们会将 Csv 文件转换为 DataTable。
它们的设计考虑了可选的引号（例如 " 符号），并且在不使用其他库的情况下尽可能多地使用：
public static DataTable GetDataTabletFromCSVFile(string filePath, bool isHeadings)
{
DataTable MethodResult = null;
try
{
using (TextFieldParser TextFieldParser = new TextFieldParser(filePath))
{
if (isHeadings)
{
MethodResult = GetDataTableFromTextFieldParser(TextFieldParser);
}
else
{
MethodResult = GetDataTableFromTextFieldParserNoHeadings(TextFieldParser);
}
}
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
public static DataTable GetDataTableFromCsvString(string csvBody, bool isHeadings)
{
DataTable MethodResult = null;
try
{
MemoryStream MemoryStream = new MemoryStream();
StreamWriter StreamWriter = new StreamWriter(MemoryStream);
StreamWriter.Write(csvBody);
StreamWriter.Flush();
MemoryStream.Position = 0;
using (TextFieldParser TextFieldParser = new TextFieldParser(MemoryStream))
{
if (isHeadings)
{
MethodResult = GetDataTableFromTextFieldParser(TextFieldParser);
}
else
{
MethodResult = GetDataTableFromTextFieldParserNoHeadings(TextFieldParser);
}
}
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
public static DataTable GetDataTableFromRemoteCsv(string url, bool isHeadings)
{
DataTable MethodResult = null;
try
{
HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
StreamReader StreamReader = new StreamReader(httpWebResponse.GetResponseStream());
using (TextFieldParser TextFieldParser = new TextFieldParser(StreamReader))
{
if (isHeadings)
{
MethodResult = GetDataTableFromTextFieldParser(TextFieldParser);
}
else
{
MethodResult = GetDataTableFromTextFieldParserNoHeadings(TextFieldParser);
}
}
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
private static DataTable GetDataTableFromTextFieldParser(TextFieldParser textFieldParser)
{
DataTable MethodResult = null;
try
{
textFieldParser.SetDelimiters(new string[] { "," });
textFieldParser.HasFieldsEnclosedInQuotes = true;
string[] ColumnFields = textFieldParser.ReadFields();
DataTable dt = new DataTable();
foreach (string ColumnField in ColumnFields)
{
DataColumn DataColumn = new DataColumn(ColumnField);
DataColumn.AllowDBNull = true;
dt.Columns.Add(DataColumn);
}
while (!textFieldParser.EndOfData)
{
string[] Fields = textFieldParser.ReadFields();
for (int i = 0; i < Fields.Length; i++)
{
if (Fields[i] == "")
{
Fields[i] = null;
}
}
dt.Rows.Add(Fields);
}
MethodResult = dt;
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
private static DataTable GetDataTableFromTextFieldParserNoHeadings(TextFieldParser textFieldParser)
{
DataTable MethodResult = null;
try
{
textFieldParser.SetDelimiters(new string[] { "," });
textFieldParser.HasFieldsEnclosedInQuotes = true;
bool FirstPass = true;
DataTable dt = new DataTable();
while (!textFieldParser.EndOfData)
{
string[] Fields = textFieldParser.ReadFields();
if(FirstPass)
{
for (int i = 0; i < Fields.Length; i++)
{
DataColumn DataColumn = new DataColumn("Column " + i);
DataColumn.AllowDBNull = true;
dt.Columns.Add(DataColumn);
}
FirstPass = false;
}
for (int i = 0; i < Fields.Length; i++)
{
if (Fields[i] == "")
{
Fields[i] = null;
}
}
dt.Rows.Add(Fields);
}
MethodResult = dt;
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
如果像我一样，您正在从报告服务中保存，那么您应该像这样使用它：
Warning[] warnings;
string[] streamids;
string mimeType;
string encoding;
string filenameExtension;
byte[] bytes = rvMain.ServerReport.Render("csv", null, out mimeType, out encoding, out filenameExtension, out streamids, out warnings);
string CsvBody = System.Text.Encoding.UTF8.GetString(bytes);
DataTable dt = GetDataTableFromCsvString(CsvBody,true);
否则，您需要做的就是：
bool IsHeadings = true; //Does the data include a heading row?
DataTable dt = GetDataTableFromCsvString(CsvBody, IsHeadings);
或者直接从 csv 文件中使用
bool IsHeadings = true; //Does the data include a heading row?
DataTable dt = GetDataTabletFromCsvFile(FilePath, IsHeadings)
或者使用远程存储的 csv 文件
bool IsHeadings = true; //Does the data include a heading row?
DataTable dt = GetDataTabletFromRemoteCsv(Url, IsHeadings)
Dataset 是 DataTables 的集合，所以像这样创建一个：
DataSet ds = new DataSet();
ds.Tables.Add(dt);
于 2016-01-22T10:56:34.963 回答
0
如果您只是想快速创建一个填充了来自 CSV 文件（或直接从 Excel 粘贴）的示例数据的 DataTable 来玩转或原型，那么您可以使用我的 Shan Carter 先生数据转换器的分支——我最近添加了该功能将逗号和制表符分隔的数据输出到 C# DataTable。
于 2015-10-31T06:44:23.577 回答