Ôàéëîâà ñèñòåìà. Ïîòîöè

Visual basic » Visual basic

bubust   òðóäíîñò:    âèäÿí: 1972

Àêî ñåëåêòèðàìå File â êîëîíàòà Class Name, ìîæåì äà ðàçãëåäàìå èíôîðìàöèÿòà â ñúñåäíàòà êîëîíà SelectedClass. Êîäúò å íà C#, íî ïî ñúùåñòâî íå å ðàçëè÷åí îò òîçè íà VB.NET.

Ïúðâîòî êîåòî çàáåëÿçâàìå å, ÷å êëàñúò íå ìîæå äà áúäå íàñëåäÿâàí - òîé å çàïå÷àòàí (saled). Âòîðîòî, êîåòî çàáåëÿçâàìå, ÷å å íàñëåäåí îò System.Object. ñëåä òîâà ñå âèæäà ÷å íÿìà íèòî ïîëåòà íèòî êîíñòðóêòîðè.

Ñëåä êàòî íÿìà êîíñòðóêòîð, çíà÷è íå ìîæåì äà ñúçäàâàìå íîâà èíñòàíöèÿ íà êëàñà. Òîçè êëàñ å ñòàòè÷åí - åäíà åäèíñòâåíà èíñòàíöèÿ íà êëàñà ñå ñïîäåëÿ íàâñÿêúäå â ïðîãðàìàòà. Ìåòîäèòå íà êëàñà ñà ñúùî ñòàòè÷íè.



from module 'c:windowsmicrosoft.netframeworkv1.1.4322mscorlib.dll'
public sealed class System.IO.File :
object
{

// Fields

// Constructors

// Methods
public static System.IO.StreamWriter AppendText(string path);
public static void Copy(string sourceFileName, string destFileName);
public static void Copy(string sourceFileName, string destFileName, bool overwrite);
public static System.IO.FileStream Create(string path);
public static System.IO.FileStream Create(string path, int bufferSize);
public static System.IO.StreamWriter CreateText(string path);
public static void Delete(string path);
public virtual bool Equals(object obj);
public static bool Exists(string path);
public static System.IO.FileAttributes GetAttributes(string path);
public static DateTime GetCreationTime(string path);
public static DateTime GetCreationTimeUtc(string path);
public virtual int GetHashCode();
public static DateTime GetLastAccessTime(string path);
public static DateTime GetLastAccessTimeUtc(string path);
public static DateTime GetLastWriteTime(string path);
public static DateTime GetLastWriteTimeUtc(string path);
public Type GetType();
public static void Move(string sourceFileName, string destFileName);
public static System.IO.FileStream Open(string path, System.IO.FileMode mode);
public static System.IO.FileStream Open(string path, System.IO.FileMode mode, System.IO.FileAccess access);
public static System.IO.FileStream Open(string path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share);
public static System.IO.FileStream OpenRead(string path);
public static System.IO.StreamReader OpenText(string path);
public static System.IO.FileStream OpenWrite(string path);
public static void SetAttributes(string path, System.IO.FileAttributes fileAttributes);
public static void SetCreationTime(string path, DateTime creationTime);
public static void SetCreationTimeUtc(string path, DateTime creationTimeUtc);
public static void SetLastAccessTime(string path, DateTime lastAccessTime);
public static void SetLastAccessTimeUtc(string path, DateTime lastAccessTimeUtc);
public static void SetLastWriteTime(string path, DateTime lastWriteTime);
public static void SetLastWriteTimeUtc(string path, DateTime lastWriteTimeUtc);
public virtual string ToString();
} // end of System.IO.File



Íåêà äà ðàçãëåäàìå ïúðâèÿ ìåòîä - AppendText. Òîé å ïóáëè÷åí, ñëåäîâàòåëíî ìîæåì äà èìàìå äîñòúï äî íåãî â íàøèòå ïðîãðàìè. Ïîíåæå å ñòàòè÷åí è íå ìîæåì äà ñúçäàâàìå íîâà èíñòàíöèÿ îò íåãî, òðÿáâà äà ãî äåêëàðèðàìå è äà ñúçäàäåì ïðîìåíëèâà îò òèï StreamWriter è äà é çàäàäåì âðúùàíàòà îò AppendText ñòîéíîñò.

Íî äà íå ãóáèì âðåìå, à äà íàïèøåì ìàëêî êîä è ñúçäàäåì ïðîãðàìêà çà ðàáîòà ñ òåêñòîâè ôàéëîâå.

Íåêà ôîðìàòà äà ñúäúðæà òðè áóòîíà (âèæ ôèãóðà 78)


Ôèãóðà 78 Ôîðìàòà ñ òðè áóòîíà è íàäïèñ Files&Streams

Ðàçãëåäàéòå êîäà. Ùðàêâàíåòî âúðõó áóòîí btnCreateFile ñúçäàâà òåêñòîâèÿ ôàéë Text.txt íà äèñê Ñ. Ùðàêâàíåòî âúðõó áóòîí btnShowFile ïðåäèçâèêâà îòâàðÿíå è ÷åòåíå íà ñúçäàäåíèÿ ôàéë Text è ïîêàçâàíå íà íåãîâîòî ñúäúðæàíèå â ñúîáùèòåëíà êóòèÿ (âèæ ôèãóðà 79)


Ôèãóðà 79

Ùðàêâàíåòî âúðõó áóòîí btnCopy êîïèðà òåêñòîâèÿ ôàéë Text.txt íà äèñê Ñ âúâ ôàéë TextCopy.txt


Option Explicit On

Option Strict On

Imports System.IO

Public Class frmFileStream

Inherits System.Windows.Forms.Form

Region " Windows Form Designer generated code "

Private Sub btnCreateFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCreateFile.Click

Dim strFileName As String = "C:Text.txt"

Dim fileStreamWriter As StreamWriter = File.AppendText(strFileName)

With fileStreamWriter

.WriteLine("This is my first textline in Text File")

.WriteLine("O o pa! The second line")

.Flush()

.Close()

End With

End Sub

Private Sub btnShowFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnShowFile.Click

Dim strFileName As String = "C:Text.txt"

Dim fileStreamReader As StreamReader = File.OpenText(strFileName)

Dim sFileContents As String

sFileContents = fileStreamReader.ReadToEnd

fileStreamReader.Close()

MessageBox.Show(sFileContents)

End Sub

Private Sub btnCopy_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCopy.Click

Dim sSource As String = "C:Text.txt"

Dim sDestination As String = "C:TextCopy.txt"

File.Copy(sSource, sDestination, True)

End Sub

End Class

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