BinaryReader.ReadChar Method
Definition
Important
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Reads the next character from the current stream and advances the current position of the stream in accordance with the Encoding used and the specific character being read from the stream.
public:
virtual char ReadChar();public virtual char ReadChar ();abstract member ReadChar : unit -> char
override this.ReadChar : unit -> charPublic Overridable Function ReadChar () As CharReturns
A character read from the current stream.
Exceptions
The end of the stream is reached.
The stream is closed.
An I/O error occurred.
A surrogate character was read.
Examples
The following code example shows how to read and write data using memory as a backing store.
using namespace System;
using namespace System::IO;
int main()
{
int i;
array<Char>^invalidPathChars = Path::InvalidPathChars;
MemoryStream^ memStream = gcnew MemoryStream;
BinaryWriter^ binWriter = gcnew BinaryWriter( memStream );
// Write to memory.
binWriter->Write( "Invalid file path characters are: " );
for ( i = 0; i < invalidPathChars->Length; i++ )
{
binWriter->Write( invalidPathChars[ i ] );
}
// Create the reader using the same MemoryStream
// as used with the writer.
BinaryReader^ binReader = gcnew BinaryReader( memStream );
// Set Position to the beginning of the stream.
binReader->BaseStream->Position = 0;
// Read the data from memory and write it to the console.
Console::Write( binReader->ReadString() );
array<Char>^memoryData = gcnew array<Char>(memStream->Length - memStream->Position);
for ( i = 0; i < memoryData->Length; i++ )
{
memoryData[ i ] = binReader->ReadChar();
}
Console::WriteLine( memoryData );
}
using System;
using System.IO;
class BinaryRW
{
static void Main()
{
int i = 0;
char[] invalidPathChars = Path.InvalidPathChars;
MemoryStream memStream = new MemoryStream();
BinaryWriter binWriter = new BinaryWriter(memStream);
// Write to memory.
binWriter.Write("Invalid file path characters are: ");
for(i = 0; i < invalidPathChars.Length; i++)
{
binWriter.Write(invalidPathChars[i]);
}
// Create the reader using the same MemoryStream
// as used with the writer.
BinaryReader binReader = new BinaryReader(memStream);
// Set Position to the beginning of the stream.
memStream.Position = 0;
// Read the data from memory and write it to the console.
Console.Write(binReader.ReadString());
char[] memoryData =
new char[memStream.Length - memStream.Position];
for(i = 0; i < memoryData.Length; i++)
{
memoryData[i] = binReader.ReadChar();
}
Console.WriteLine(memoryData);
}
}
open System.IO
let invalidPathChars = Path.GetInvalidPathChars()
let memStream = new MemoryStream()
let binWriter = new BinaryWriter(memStream)
// Write to memory.
binWriter.Write "Invalid file path characters are: "
for i = 0 to invalidPathChars.Length - 1 do
binWriter.Write invalidPathChars[i]
// Create the reader using the same MemoryStream
// as used with the writer.
let binReader = new BinaryReader(memStream)
// Set Position to the beginning of the stream.
memStream.Position <- 0
// Read the data from memory and write it to the console.
printf $"{binReader.ReadString()}"
let memoryData = Array.zeroCreate<char> (int (memStream.Length - memStream.Position))
for i = 0 to memoryData.Length - 1 do
memoryData[i] <- binReader.ReadChar()
printfn $"{memoryData}"
Imports System.IO
Public Class BinaryRW
Shared Sub Main()
Dim i As Integer = 0
Dim invalidPathChars() As Char = Path.InvalidPathChars
Dim memStream As new MemoryStream()
Dim binWriter As New BinaryWriter(memStream)
' Write to memory.
binWriter.Write("Invalid file path characters are: ")
For i = 0 To invalidPathChars.Length - 1
binWriter.Write(invalidPathChars(i))
Next i
' Create the reader using the same MemoryStream
' as used with the writer.
Dim binReader As New BinaryReader(memStream)
' Set Position to the beginning of the stream.
memStream.Position = 0
' Read the data from memory and write it to the console.
Console.Write(binReader.ReadString())
Dim memoryData( _
CInt(memStream.Length - memStream.Position) - 1) As Char
For i = 0 To memoryData.Length - 1
memoryData(i) = binReader.ReadChar()
Next i
Console.WriteLine(memoryData)
End Sub
End Class
Remarks
If the ReadChar method attempts to read a surrogate character in the stream an exception will be raised and the position in the stream will advance. The position is restored to the original location before ReadChar was called if the stream is seekable; however, if the stream is unseekable, the position will not be corrected. If surrogate characters can be expected in the stream, use the ReadChars method instead.
Because of data formatting conflicts, using this method with the following encodings is not recommended:
UTF-7
ISO-2022-JP
ISCII
For a list of common I/O tasks, see Common I/O Tasks.
