Chapter 2 Part 15:

What do we have in this chapter 2 Part 15?

C# StreamReader and StreamWriter Program Example

Note: If you want to experience a complete C++ .NET/C++-CLI programming tutorial please jump to Visual C++ .NET programming tutorial.

Create a new CLR console application project and you might want to use SimpleWriterReaderCP as the project and solution names.

Add the following code.

// SimpleWriterReaderCP.cpp : main project file.

using namespace System;

using namespace System::IO;

int main( array ^args)

String^ path = L «c:\\temp\\MyTestFile0.txt» ;

Console::WriteLine(L «Writing some text to <0>» , path);

StreamWriter^ sw = gcnew StreamWriter(path);

sw->WriteLine( «is some text» );

sw->WriteLine( «written to test» );

sw->WriteLine( «for reading. » );

Console::WriteLine( «Reading the previously written text..» );

FileStream^ fs = gcnew FileStream(path, FileMode::Open);

StreamReader^ sr = gcnew StreamReader(fs);

while (sr->Peek() >= 0)

catch (Exception^ e)

Console::WriteLine( «The process failed: <0>» , e->ToString());

Build and run the project. The following is an output example.

You can try opening the created text file and in this case is shown below.

C# StreamReader and StreamWriter Example

Create a new console application project and add the following code.

static void Main( string [] args)

string path = @»c:\temp\MyTestFile.txt» ;

if ( File .Exists(path))

Console .WriteLine( «Writing some text to <0>» , path);

using ( StreamWriter sw = new StreamWriter (path))

sw.WriteLine( «is some text» );

sw.WriteLine( «written to test» );

sw.WriteLine( «for reading. » );

Console .WriteLine( «Reading the previously written text..» );

using ( FileStream fs = new FileStream (path, FileMode .Open))

using ( StreamReader sr = new StreamReader (fs))

while (sr.Peek() >= 0)

catch ( Exception e)

Console .WriteLine( «The process failed: <0>» , e.ToString());

An output sample:

VB .NET StreamReader and StreamWriter Example

Create a new console application project and add the following code.

Dim path As String = «c:\temp\MyTestVB.txt»

Console.WriteLine( «Deleting » + path + » if exists. » )

If File.Exists(path) Then

Console.WriteLine( «Then, creating a » + path + » file» )

Dim sw As StreamWriter = New StreamWriter(path)

Console.WriteLine( «Writing some text to the created file. » )

sw.WriteLine( «is some text» )

sw.WriteLine( «written to test» )

sw.WriteLine( «for reading. » )

Dim fs As FileStream = New FileStream(path, FileMode.Open)

Console.WriteLine( «Open » + path + » for reading» )

Dim sr As StreamReader = New StreamReader(fs)

Чтение txt-файла с помощью StreamReader-а

доброго времени суток.
вопрос такой: как считать информацию из *.txt файла с помощью streamreader?

файл был создан таким образом:

StreamReader не читает русские буквы из файла .txt
Пишу метод, который читает значения из файла txt по значению. Особо в нете не прошарен, если есть.

Чтение через StreamReader HTML файла
Через StreamReader я читаю HTML файл В Debug все работает как надо, но при запуске через .EXE .

Чтение из файла ‘New.txt’, запись четных строк в ‘1.txt’, а нечетных в ‘2.txt’
В общем все работает, но есть «НО», иначе бы не открывал тему. Содержимое исходного файла: 1 1 1.

Чтение данных с одного txt файла, запись данных во второй txt в определенную позицию
Добрый день, уважаемые форумчане! Нужна ваша помощь. Задача поставлена так: существует файл.

Добавлено через 35 минут
Точнее говоря, System::IO::File::CreateText возвращает StreamWriter ^ , который является write-only потоком, поэтому в StreamReader преобразовать не получится, просто создаете объект класса StreamReader и инициализируете вызовом OpenText, когда StreamWriter уже закрыт

Ma3a,
я чето совсем запутался.
Вот смотрите задачу:
1.в файл «1.txt» пишется строка из textBox1->Text.
2.строка читается из файла в программу. (в 1 и 2 я сделал именно так, ибо не знал как из string^ сделать char[])
3.в программе каждый символ этой строки кодируется опеределенным словом и записывается в «2.txt» (например слово «мама» будет выводиться в файл как «%D0%BC%D0%B0%D0%BC%D0%B0»)
4.далее, из файла «2.txt» строка читается в textBox2->Text.

вот как-то так.самое сложное тут — это реализовать перекодирование символов. в консольном приложении я это кое-как написал, вот примерный код:

А зачем вам тогда из String ^ опять в native тип переводить, чтобы надо было опять в String ^ перегонять дабы заполнить TextBox1->Text ?

просто делаете свои дела с перекодированием, на этом этапе у вас будет заполнен массив str или что там используется для вывода в файл, в общем выводите это в 2.txt, слизываете это StreamReader’ом так же как и на шаге 2, и заполняете textbox

Заказываю контрольные, курсовые, дипломные и любые другие студенческие работы здесь или здесь.

Чтение из файла txt
Каким образом правильно использовать метод ReadAllText или как прочитать весь текст из файла .txt.

Чтение из txt файла
Имеется txt файл. В нем написан текст, а между текстами знаки «=========». То есть нужно читать.

Чтение из txt файла
Здравствуйте. Есть программа, хочу сделать в ней чтение из txt файла через StreamReader но почему.

Чтение из txt файла
Есть готовая программа, но она очень геморройная. Нужно ввести 12 оценок каждому ученику, а их там.

Stream Reader Class

Definition

Implements a TextReader that reads characters from a byte stream in a particular encoding.

Examples

The following example uses an instance of StreamReader to read text from a file. The constructor used in this example is not supported for use in Windows Store Apps.

The following example instantiates a StreamReader object and calls its ReadAsync method to read a file asynchronously.

Remarks

StreamReader is designed for character input in a particular encoding, whereas the Stream class is designed for byte input and output. Use StreamReader for reading lines of information from a standard text file.

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try / catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the «Using an Object that Implements IDisposable» section in the IDisposable interface topic.

StreamReader defaults to UTF-8 encoding unless specified otherwise, instead of defaulting to the ANSI code page for the current system. UTF-8 handles Unicode characters correctly and provides consistent results on localized versions of the operating system. If you get the current character encoding using the CurrentEncoding property, the value is not reliable until after the first Read method, since encoding auto detection is not done until the first call to a Read method.

By default, a StreamReader is not thread safe. See TextReader.Synchronized for a thread-safe wrapper.

The Read(Char[], Int32, Int32) and Write(Char[], Int32, Int32) method overloads read and write the number of characters specified by the count parameter. These are to be distinguished from BufferedStream.Read and BufferedStream.Write, which read and write the number of bytes specified by the count parameter. Use the BufferedStream methods only for reading and writing an integral number of byte array elements.

When reading from a Stream, it is more efficient to use a buffer that is the same size as the internal buffer of the stream.

For a list of common I/O tasks, see Common I/O Tasks.

Constructors

Initializes a new instance of the StreamReader class for the specified stream.

Initializes a new instance of the StreamReader class for the specified stream, with the specified byte order mark detection option.

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding.

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding and byte order mark detection option.

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding, byte order mark detection option, and buffer size.

Initializes a new instance of the StreamReader class for the specified stream based on the specified character encoding, byte order mark detection option, and buffer size, and optionally leaves the stream open.

Initializes a new instance of the StreamReader class for the specified file name.

Initializes a new instance of the StreamReader class for the specified file name, with the specified byte order mark detection option.

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding.

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding and byte order mark detection option.

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding, byte order mark detection option, and buffer size.

Fields

A StreamReader object around an empty stream.

Properties

Returns the underlying stream.

Gets the current character encoding that the current StreamReader object is using.

Gets a value that indicates whether the current stream position is at the end of the stream.

Methods

Closes the StreamReader object and the underlying stream, and releases any system resources associated with the reader.

Closes the TextReader and releases any system resources associated with the TextReader .

(Inherited from TextReader)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

(Inherited from MarshalByRefObject)

Clears the internal buffer.

Releases all resources used by the TextReader object.

(Inherited from TextReader)

Closes the underlying stream, releases the unmanaged resources used by the StreamReader, and optionally releases the managed resources.

Determines whether the specified object is equal to the current object.

(Inherited from Object)

Serves as the default hash function.

(Inherited from Object)

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

(Inherited from MarshalByRefObject)

Gets the Type of the current instance.

(Inherited from Object)

Obtains a lifetime service object to control the lifetime policy for this instance.

(Inherited from MarshalByRefObject)

Creates a shallow copy of the current Object.

(Inherited from Object)

Creates a shallow copy of the current MarshalByRefObject object.

(Inherited from MarshalByRefObject)

Returns the next available character but does not consume it.

Reads the next character from the input stream and advances the character position by one character.

Reads a specified maximum of characters from the current stream into a buffer, beginning at the specified index.

Reads the characters from the current stream into a span.

Reads the characters from the current reader and writes the data to the specified buffer.

(Inherited from TextReader)

Reads a specified maximum number of characters from the current stream asynchronously and writes the data to a buffer, beginning at the specified index.

Reads a specified maximum number of characters from the current text reader asynchronously and writes the data to a buffer, beginning at the specified index.

(Inherited from TextReader)

Asynchronously reads the characters from the current stream into a memory block.

Asynchronously reads the characters from the current stream into a memory block.

(Inherited from TextReader)

Reads a specified maximum number of characters from the current stream and writes the data to a buffer, beginning at the specified index.

Reads a specified maximum number of characters from the current text reader and writes the data to a buffer, beginning at the specified index.

(Inherited from TextReader)

Reads the characters from the current stream and writes the data to a buffer.

Reads the characters from the current stream and writes the data to a buffer.

(Inherited from TextReader)

Reads a specified maximum number of characters from the current stream asynchronously and writes the data to a buffer, beginning at the specified index.

Reads a specified maximum number of characters from the current text reader asynchronously and writes the data to a buffer, beginning at the specified index.

(Inherited from TextReader)

Asynchronously reads the characters from the current stream and writes the data to a buffer.

Asynchronously reads the characters from the current stream and writes the data to a buffer.

(Inherited from TextReader)

Reads a line of characters from the current stream and returns the data as a string.

Reads a line of characters asynchronously from the current stream and returns the data as a string.

Reads a line of characters asynchronously and returns the data as a string.

(Inherited from TextReader)

Reads all characters from the current position to the end of the stream.

Reads all characters from the current position to the end of the stream asynchronously and returns them as one string.

Reads all characters from the current position to the end of the text reader asynchronously and returns them as one string.

(Inherited from TextReader)

Returns a string that represents the current object.

(Inherited from Object)

CreateObjRef(Type)

DiscardBufferedData()

Dispose(Boolean)

GetHashCode()

GetLifetimeService()

GetType()

InitializeLifetimeService()

MemberwiseClone()

MemberwiseClone(Boolean)

Peek()

ReadAsync(Char[], Int32, Int32)

ReadAsync(Memory , CancellationToken)

ReadBlock(Char[], Int32, Int32)

ReadBlock(Span )

ReadBlockAsync(Char[], Int32, Int32)

ReadBlockAsync(Memory , CancellationToken)

ReadLine()

ReadToEnd()

ToString()

Explicit Interface Implementations

For a description of this member, see Dispose().