csvexport.cs

using System;
using System.IO;
namespace CSVExport {
public class CSVExport {
		private static string CsvEscape( object value ) {
			if(value is null) {
				return string.Empty;
			}
			string str = value.ToString( );
			return @"""" + str.Replace( @"""", @"""""" ) + @"""";
		}

		private static void StartCSV<T>( T obj, string file_path, bool overwrite = false ) {
			if(File.Exists( file_path ) && !overwrite) {
				return;
			}
			using(var fs = File.CreateText( file_path )) {
				bool first = true;
				foreach(var prop in typeof( T ).GetProperties( )) {
					if(Attribute.IsDefined( prop, typeof( System.ComponentModel.BrowsableAttribute ) )) {
						continue;
					}

					string item = string.Empty;
					if(!first) {
						item += @",";
					}
					first = false;
					item += $@"{CsvEscape( prop.Name )}";
					fs.Write( item );
				}
				fs.Write( "\r\n" );
				fs.Flush( );
			}
		}

		public static void AppendCSV<T>( T obj, string file_path ) {
			var start_time = DateTime.Now;
			try {
				StartCSV( obj, file_path );
				using(var fs = File.AppendText( file_path )) {
					bool first = true;
					foreach(var prop in typeof( T ).GetProperties( )) {
						if(Attribute.IsDefined( prop, typeof( System.ComponentModel.BrowsableAttribute ) )) {
							continue;
						}
						string item = string.Empty;
						if(!first) {
							item += @",";
						}
						first = false;
						item += $@"{CsvEscape( prop.GetValue( obj, null ) )}";
						fs.Write( item );
					}
					fs.Write( "\r\n" );
					fs.Flush( );
				}
			} finally {
				System.Diagnostics.Debug.WriteLine( $@"AppendCSV to {file_path} took {new FormattedTimeSpan( DateTime.Now - start_time )}" );
			}
		}
	}
 }