How to create CSV Excel file C#? [closed]

Answer 1

Thanks a lot for that! I modified the class to:

• use a variable delimiter, instead of hardcoded in code
• replacing all newLines (\n \r \n\r) in MakeValueCsvFriendly

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data.SqlTypes;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;

    public class CsvExport
    {

        public char delim = ';';
        /// 

        /// To keep the ordered list of column names
        /// 
        List fields = new List();

        /// 

        /// The list of rows
        /// 
        List> rows = new List>();

        /// 

        /// The current row
        /// 
        Dictionary currentRow { get { return rows[rows.Count - 1]; } }

        /// 

        /// Set a value on this column
        /// 
        public object this[string field]
        {
            set
            {
                // Keep track of the field names, because the dictionary loses the ordering
                if (!fields.Contains(field)) fields.Add(field);
                currentRow[field] = value;
            }
        }

        /// 

        /// Call this before setting any fields on a row
        /// 
        public void AddRow()
        {
            rows.Add(new Dictionary());
        }

        /// 

        /// Converts a value to how it should output in a csv file
        /// If it has a comma, it needs surrounding with double quotes
        /// Eg Sydney, Australia -> "Sydney, Australia"
        /// Also if it contains any double quotes ("), then they need to be replaced with quad quotes[sic] ("")
        /// Eg "Dangerous Dan" McGrew -> """Dangerous Dan"" McGrew"
        /// 
        string MakeValueCsvFriendly(object value)
        {
            if (value == null) return "";
            if (value is INullable && ((INullable)value).IsNull) return "";
            if (value is DateTime)
            {
                if (((DateTime)value).TimeOfDay.TotalSeconds == 0)
                    return ((DateTime)value).ToString("yyyy-MM-dd");
                return ((DateTime)value).ToString("yyyy-MM-dd HH:mm:ss");
            }
            string output = value.ToString();
            if (output.Contains(delim) || output.Contains("\""))
                output = '"' + output.Replace("\"", "\"\"") + '"';
            if (Regex.IsMatch(output,  @"(?:\r\n|\n|\r)"))
                output = string.Join(" ", Regex.Split(output, @"(?:\r\n|\n|\r)"));
            return output;
        }

        /// 

        /// Output all rows as a CSV returning a string
        /// 
        public string Export()
        {
            StringBuilder sb = new StringBuilder();

            // The header
            foreach (string field in fields)
                sb.Append(field).Append(delim);
            sb.AppendLine();

            // The rows
            foreach (Dictionary row in rows)
            {
                foreach (string field in fields)
                    sb.Append(MakeValueCsvFriendly(row[field])).Append(delim);
                sb.AppendLine();
            }

            return sb.ToString();
        }

        /// 

        /// Exports to a file
        /// 
        public void ExportToFile(string path)
        {
            File.WriteAllText(path, Export());
        }

        /// 

        /// Exports as raw UTF8 bytes
        /// 
        public byte[] ExportToBytes()
        {
            return Encoding.UTF8.GetBytes(Export());

        }

    }