We often read or write a file(.txt, .xls etc.), and we can achieve it through following common class.


using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.IO;
using Excel;
using System.Runtime.InteropServices;

namespace OF_Common
{
    public class fileHelper
    {
        public string readLabelFile(string strFilePathName)
        {
            string strLabel="";
            string strLine = "";
            try
            {
                FileStream file = new FileStream(strFilePathName, FileMode.Open, FileAccess.Read);
                StreamReader sr = new StreamReader(file, Encoding.UTF8);
                while ((strLine = sr.ReadLine()) != null)
                {
                    if (strLine != "")
                    {
                        strLabel = strLabel + strLine;
                    }
                }
                sr.Close();
                file.Close();
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message, ex);
            }
            return strLabel;
        }
        public string readFromFile(string strFilePathName)
        {
            string strContent = "";
            StreamReader sr = null;
            Encoding ecType = Encoding.Default;
            try
            {
                sr = new StreamReader(strFilePathName, ecType);
                strContent = sr.ReadToEnd();
            }
            catch (Exception e)
            {
                throw new Exception(e.Message, e);
            }
            finally
            {
                sr.Close();
            }
            return strContent;
        }
        public bool WriteFile(string strFilePath, string strContent, bool bolOverWrite)
        {
            Encoding ecType = Encoding.Default;
            bool bolResult = true;
            StreamWriter sw = null;

            try
            {
                sw = new StreamWriter(strFilePath, !bolOverWrite, ecType);
                sw.Write(strContent);
            }
            catch (Exception Ex)
            {
                throw new Exception(Ex.Message, Ex);
            }
            finally
            {
                sw.Close();
            }
            return bolResult;
        }
        public void genDTExcel(string strFilePath, System.Data.DataTable dt)
        {
            try
            {
                Excel.Application xlApp = new Excel.ApplicationClass();
                int rowIndex;
                int colIndex;
                rowIndex = 1;
                colIndex = 0;
                Excel.Workbook xlBook = xlApp.Workbooks.Add(true);
                xlApp.Visible = false;
                if (dt.Rows.Count > 0)
                {
                    Excel.Range range = xlApp.get_Range(xlApp.Cells[1, 1], xlApp.Cells[1, dt.Columns.Count]);
                    range.Font.Size = 9;//单元字体大小
                    range.Font.Bold = true;
                    range.Font.Color = System.Drawing.Color.White.ToArgb(); ;//单元字体顔色
                    range.Interior.Color = System.Drawing.Color.MediumBlue.ToArgb();//单元背景
                    range.Font.Name = "Arial";//单元字体字体名称
                    range.Borders.LineStyle. = 1;

                    Excel.Range range1 = xlApp.get_Range(xlApp.Cells[2, 1], xlApp.Cells[dt.Rows.Count + 1, dt.Columns.Count]);
                    range1.Font.Size = 9;//单元字体大小
                    range1.Font.Color = System.Drawing.Color.Black.ToArgb(); ;//单元字体顔色
                    range1.Interior.Color = System.Drawing.Color.LemonChiffon.ToArgb();//单元背景
                    range1.Font.Name = "Arial";//单元字体字体名称
                    range1.Borders.LineStyle. = 1;

                    foreach (DataColumn colu in dt.Columns)
                    {
                        colIndex = colIndex + 1;
                        xlApp.Cells[1, colIndex] = colu.ColumnName;
                    }
                    //得到的表所有行,赋值给单元格
                    for (int row = 0; row < dt.Rows.Count; row++)
                    {
                        rowIndex = rowIndex + 1;
                        colIndex = 0;
                        for (int col = 0; col < dt.Columns.Count; col++)
                        {
                            colIndex = colIndex + 1;
                            xlApp.Cells[rowIndex, colIndex] = dt.Rows[row][col].ToString();
                        }
                    }
                }
                else
                {
                    System.Windows.Forms.Application.Exit();
                }

                xlApp.Cells.EntireColumn.AutoFit();

                Excel.Range range2 = xlApp.get_Range(xlApp.Cells[2, 1], xlApp.Cells[dt.Rows.Count + 1, 1]);
                range2.Font.Size = 9;//单元字体大小
                range2.Font.Color = System.Drawing.Color.Black.ToArgb(); ;//单元字体颜色
                range2.Interior.Color = System.Drawing.Color.LemonChiffon.ToArgb();//单元背景
                range2.Font.Name = "Arial";
                range2.Borders.LineStyle. = 1;
                //range2.NumberFormatLocal = "@";
                range2.NumberFormatLocal = "###############";

                Excel.Range range3 = xlApp.get_Range(xlApp.Cells[2, 2], xlApp.Cells[dt.Rows.Count + 1, dt.Columns.Count]);
                range3.Font.Size = 9;//单元字体大小
                range3.Font.Color = System.Drawing.Color.Black.ToArgb(); ;//单元字体颜色
                range3.Interior.Color = System.Drawing.Color.LemonChiffon.ToArgb();//单元背景
                range3.Font.Name = "Arial";
                range3.Borders.LineStyle. = 1;
                range3.NumberFormatLocal = "@";

                xlApp.Cells.VerticalAlignment = Excel.Constants.xlCenter;
                xlApp.Cells.HorizontalAlignment = Excel.Constants.xlCenter;
                xlBook.SaveAs(strFilePath + DateTime.Now.ToString("HHmmss") + ".XLS", Excel.XlFileFormat.xlXMLSpreadsheet, null, null, false, false, Excel.XlSaveAsAccessMode.xlNoChange, null, null, null, null, null);
                xlApp.Application.Workbooks.Close();
                xlApp.Application.Quit();
                xlApp.Quit();
                System.Runtime.InteropServices.Marshal.ReleaseComObject(xlBook);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
                GC.Collect(0);
            }
            catch (Exception e)
            {
                throw e;
            }
        }
        public void genGeneralExcel(string strFilePath, System.Data.DataTable dt)
        {
            try
            {
                string header = "";
                string items = "";
                string strPath = strFilePath +"_"+ DateTime.Now.ToString("HHmmss") + ".XLS";
                StreamWriter sw = new StreamWriter(strPath, true);
                foreach (DataColumn colu in dt.Columns)
                {
                    header += colu.ColumnName.Trim('\t') + '\t';
                }
                header = header.TrimEnd('\t');
                sw.WriteLine(header);
                for (int row = 0; row < dt.Rows.Count; row++)
                {
                    items = "";
                    for (int col = 0; col < dt.Columns.Count; col++)
                    {
                        items += dt.Rows[row][col].ToString().Trim('\r').Trim('\n').Trim('\t') + '\t';
                    }
                    items = items.TrimEnd('\t');
                    sw.WriteLine(items);
                }
                sw.Close();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
    }
}