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c#中对文件的操作小结
1、建立一个文本文件 public class FileClass { public static void Main() { WriteToFile(); } static void WriteToFile() { StreamWriter SW; SW=File.CreateText("c:\MyTextFile.txt"); SW.WriteLine("God is greatest of them all"); SW.WriteLine("This is second line"); SW.Close(); Console.WriteLine("File Created SucacessFully"); } } 2、读文件 public class FileClass { public static void Main() { ReadFromFile("c:\MyTextFile.txt"); } static void ReadFromFile(string filename) { StreamReader SR; string S; SR=File.OpenText(filename); S=SR.ReadLine(); while(S!=null) { Console.WriteLine(S); S=SR.ReadLine(); } SR.Close(); } } 3、追加操作 public class FileClass { public static void Main() { AppendToFile(); } static void AppendToFile() { StreamWriter SW; SW=File.AppendText("C:\MyTextFile.txt"); SW.WriteLine("This Line Is Appended"); SW.Close(); Console.WriteLine("Text Appended Successfully"); } } 4、下载文件(From DataBase Read) int FileID=Convert.ToInt32(DataList_Event_AttachFile.DataKeys[e.Item.ItemIndex]); string sql="select FileName,File_Data,File_Type from AttachFile where FileID="+FileID; Amcham.Data d=new Amcham.Data(); Amcham.Data.DataResult ds=new Amcham.Data.DataResult(); ds=d.GetSearchResult(sql); if (ds.dr.Read()) { byte[] Buffer=new byte[ds.dr.GetSqlBinary(1).Length]; ds.dr.GetBytes(1,0,Buffer,0,Buffer.Length); Response.ContentType=ds.dr.GetSqlString(2).ToString(); Response.AddHeader("Content-Disposition", "attachment; filename=\"" + ds.dr.GetSqlString(0).ToString() + "\""); Response.BinaryWrite(Buffer); Response.End();//避免把页面HTML代码写入文件尾部 5、读附件入数据库 FileStream=file.PostedFile.InputStream; FileLen=file.PostedFile.ContentLength; FileName=Path.GetFileName(file.PostedFile.FileName); FileType=file.PostedFile.ContentType; byte[] FileContent=new byte[FileLen]; FileStream.Read(FileContent,0,FileLen); AttachFile.FileName=FileName; AttachFile.File_data=FileContent; AttachFile.FileType=FileType; AttachFile.EventID=EventID; AttachFile.AddAttach(); public class AttachFile { public System.Data.SqlTypes.SqlInt32 AttachID; public System.Data.SqlTypes.SqlInt32 EventID; public System.Data.SqlTypes.SqlInt32 SpeakerID; public System.Data.SqlTypes.SqlString FileName; public System.Data.SqlTypes.SqlString FileType; public byte[] File_data; public int AddAttach() { string InsertSql="INSERT INTO AttachFile(FileID, EventID, SpeakerID, FileName,File_Type, File_data) VALUES (@" + "FileID, @EventID, @SpeakerID, @FileName,@FileType, @File_data)"; SqlConnection myConnection = new SqlConnection(amcham.Data.ConDB.ConnectionString); SqlCommand myCommand = new SqlCommand(InsertSql, myConnection); // Add Parameters myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@FileID", System.Data.SqlDbType.Int)); myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@EventID", System.Data.SqlDbType.Int)); myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@SpeakerID", System.Data.SqlDbType.Int)); myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@FileName", System.Data.SqlDbType.VarChar, 50)); myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@File_data", System.Data.SqlDbType.Image)); myCommand.Parameters.Add(new System.Data.SqlClient.SqlParameter("@FileType", System.Data.SqlDbType.VarChar, 50)); // Add Value this.AttachID=this.GetNewAttachID(); myCommand.Parameters["@FileID"].Value=this.AttachID; myCommand.Parameters["@EventID"].Value=this.EventID; myCommand.Parameters["@SpeakerID"].Value=this.SpeakerID; myCommand.Parameters["@FileName"].Value=this.FileName; myCommand.Parameters["@File_data"].Value=this.File_data; myCommand.Parameters["@FileType"].Value=this.FileType; // Execute the command try { // Open the connection and execute the Command myCommand.Connection.Open(); myCommand.ExecuteNonQuery(); return (int)(this.AttachID); } catch (Exception e) { // An error occurred, pass the exception up Event throw e; } } |
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