How to Read and Write Text File Using StreamReader and StreamWriter in Dynamics Ax

Description:-

AX provides several ways of writing files. Depending upon scenario, you can use one. Apart from AX native filing, you can also use .NET interop to call .NET classes for reading/writing files. We will be showing few classes which are provided by AX for writing files.

StreamReader and StreamWriter

Implements a TextReader that reads characters from a byte stream in a particular encoding.Implements a TextWriter for writing characters to a stream in a particular encoding.

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Length: Gets the length (in bytes) of the stream. Position: Gets or sets the current position in the stream for reading and writing operations. Seek(): Sets the position within the stream. Flush(): Clears any buffers within the stream and forces changes to be written to the underlying system or device. Some streams have the AutoFlush property for flushing automatically any change. Close(): Closes the stream and releases any resources associated with it. !!! Remember always close the stream !!! Read(): Performs a sequential read of a specified number of bytes from the current position and updates the position to the end of the read upon completion of the operation. ReadByte(): Performs the read of a single byte and updates the position by moving it by one. Write(): Writes information to the stream as a number of bytes and updates the current position to reflect the new write position. WriteByte(): Writes a single byte to the stream and updates the position.

There are a lot of streams, some of them:

FileStream

MemoryStream

CryptoStream

NetworkStream

GZipStream

The File class
The File class provides methods for easy writing and reading operations.

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Copy(): Copies a file to a new file. !!! The new file must not exist or an event will be thrown. !!! Move(): Moves a file from one place to another. !!! The target file must not exist or an event will be thrown. !!! Delete(): Deletes a file. !!! None exception is throw if file doesn't exists !!! Exists(): Returns true if a file exists. AppendText(): Opens a file (or creates a new file if one does not exist) and returns a StreamWriter that is prepared to allow text to be appended to the file. CreateText(): Creates or opens a file and returns a StreamWriter object that is ready to have text written into it. OpenText(): Opens an existing file and returns a StreamReaderobject. Open(): Opens an existing file and returns a FileStream object. We can specify the file mode and the file access type. OpenRead(): Opens an existing file and returns a read-only FileStream object. OpenWrite(): Opens an existing file for writing and returns a FileStream object. Create(): Creates a new file and returns a FileStream object. Atomic operations: ReadAllBytes(): Opens a file, reads the contents of it into a byte array, and closes the file. ReadAllLines(): Opens a file, reads the contents of it into an array of strings (one per line), and closes the file. ReadAllText(): Opens a file, reads the contents of it into a string, and closes the file. WriteAllBytes(): Opens a file, writes the contents of a byte array into it (overwriting any existing data), and closes the file. WriteAllLines(): Opens a file, writes the contents of a string array into it (overwriting any existing data), and closes. WriteAllText(): Opens a file, writes the contents of a string into it (overwriting any existing data), and closes the file.

Read Text using StreamReader

static void ReadTextStreamReader(Args _args)
{
  System.IO.StreamReader   reader;
  System.String  line;
  InteropPermissioninteropPermission;
  strtext,filepath;
  containerconfilter =['.txt','*.txt'];
  A_PurchaseOrder objA_PurchaseOrder;
  filepath = WinAPI::getOpenFileName(
    0,
    confilter,
    "",
    "Save As",
    "",
    "Untitled");
  interopPermission = newInteropPermission(InteropKind::ClrInterop);
  interopPermission.assert();
  reader = new System.IO.StreamReader(filepath,System.Text.Encoding::get_UTF7());
  line = reader.ReadLine();
  while (!System.String::IsNullOrEmpty(line))
  {
    line = reader.ReadLine();
    text  =System.Convert::ToString(line);
    info(text);
  }
  CodeAccessPermission::revertAssert();
  reader.Close();
  reader.Dispose();   
}

Write Text Using StreamReader

static void WriteFileStreamReader(Args _args)
{
  System.IO.StreamWriter     writer;
  InteropPermission interopPermission;
  strtext,filepath;
  containerconfilter =['.txt','*.txt'];
  A_PurchaseOrder objA_PurchaseOrder;
  filepath = WinAPI::getSaveFileName(
    0,
    confilter,
    "",
    "Save As",
    "",
    "Untitled");
  writer = new System.IO.StreamWriter(filepath);
  interopPermission = new InteropPermission(InteropKind::ClrInterop);
  interopPermission.assert();
  whileselectobjA_PurchaseOrder
  {
    writer.WriteLine(strFmt("%1|%2|%3|%4|%5", objA_PurchaseOrder.Purchase_ID,
      objA_PurchaseOrder.Vender_Code,
      enum2str(objA_PurchaseOrder.Status), 
      date2str(objA_PurchaseOrder.Purchase_Date,123,
            DateDay::Digits2,DateSeparator::Hyphen,
            DateMonth::Digits2,DateSeparator::Hyphen,
            DateYear::Digits4),
            objA_PurchaseOrder.Purchase_Amount));
  }
  writer.Flush();
  writer.Close();
  writer.Dispose();
  CodeAccessPermission::revertAssert();
}

Author : Umesh Patel

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