c#中对文件的操作小结

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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;
    }

}