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Convert.ToBase64CharArray Method (Byte[], Int32, Int32, Char[], Int32)

Converts a subset of an 8-bit unsigned integer array to an equivalent subset of a Unicode character array encoded with base 64 digits. Parameters specify the subsets as offsets in the input and output arrays, and the number of elements in the input array to convert.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static int ToBase64CharArray (
	byte[] inArray,
	int offsetIn,
	int length,
	char[] outArray,
	int offsetOut
)
public static int ToBase64CharArray (
	byte[] inArray, 
	int offsetIn, 
	int length, 
	char[] outArray, 
	int offsetOut
)
public static function ToBase64CharArray (
	inArray : byte[], 
	offsetIn : int, 
	length : int, 
	outArray : char[], 
	offsetOut : int
) : int

Parameters

inArray

An input array of 8-bit unsigned integers.

offsetIn

A position within inArray.

length

The number of elements of inArray to convert.

outArray

An output array of Unicode characters.

offsetOut

A position within outArray.

Return Value

A 32-bit signed integer containing the number of bytes in outArray.

Exception typeCondition

ArgumentNullException

inArray or outArray is a null reference (Nothing in Visual Basic).

ArgumentOutOfRangeException

offsetIn, offsetOut, or length is negative.

-or-

offsetIn plus length is greater than the length of inArray.

-or-

offsetOut plus the number of elements to return is greater than the length of outArray.

The subset of length elements of inArray starting at position offsetIn, are taken as a numeric value and converted to a subset of elements in outArray starting at position offsetOut. The return value indicates the number of converted elements in outArray. The subset of outArray consists of base 64 digits.

The base 64 digits in ascending order from zero are the uppercase characters 'A' to 'Z', the lowercase characters 'a' to 'z', the numerals '0' to '9', and the symbols '+' and '/'. The valueless character, '=', is used for trailing padding.

The offset and length parameters are 32-bit signed numbers. The offsetIn and offsetOut parameters are zero-based array positions.

The following code example demonstrates using the ToBase64CharArray method to UUencode (encode in base 64) a binary stream, then save the encoding to a file.

public void EncodeWithCharArray() {
    System.IO.FileStream inFile;     
    byte[]                 binaryData;

    try {
        inFile = new System.IO.FileStream(inputFileName,
                                          System.IO.FileMode.Open,
                                          System.IO.FileAccess.Read);
        binaryData = new Byte[inFile.Length];
        long bytesRead = inFile.Read(binaryData, 0,
                                    (int) inFile.Length);
        inFile.Close();
    }
    catch (System.Exception exp) {
        // Error creating stream or reading from it.
        System.Console.WriteLine("{0}", exp.Message);
        return;
    }

    // Convert the binary input into Base64 UUEncoded output.
    // Each 3 byte sequence in the source data becomes a 4 byte
    // sequence in the character array. 
    long arrayLength = (long) ((4.0d/3.0d) * binaryData.Length);
    
    // If array length is not divisible by 4, go up to the next
    // multiple of 4.
    if (arrayLength % 4 != 0) {
        arrayLength += 4 - arrayLength % 4;
    }
    
    char[] base64CharArray = new char[arrayLength];
    try {
        System.Convert.ToBase64CharArray(binaryData, 
                                         0,
                                         binaryData.Length,
                                         base64CharArray,
                                         0);
    }
    catch (System.ArgumentNullException) {
        System.Console.WriteLine("Binary data array is null.");
        return;
    }
    catch (System.ArgumentOutOfRangeException) {
        System.Console.WriteLine("Char Array is not large enough.");
        return;
    }

    // Write the UUEncoded version to the output file.
    System.IO.StreamWriter outFile; 
    try {
        outFile = new System.IO.StreamWriter(outputFileName,
                                        false,
                                        System.Text.Encoding.ASCII);             
        outFile.Write(base64CharArray);
        outFile.Close();
    }
    catch (System.Exception exp) {
        // Error creating stream or writing to it.
        System.Console.WriteLine("{0}", exp.Message);
    }
}

public void EncodeWithCharArray()
{
    System.IO.FileStream inFile;
    ubyte binaryData[];

    try {
        inFile = new System.IO.FileStream(inputFileName, 
                                          System.IO.FileMode.Open,
                                          System.IO.FileAccess.Read );
        binaryData = new ubyte[(int)inFile.get_Length()];

        long bytesRead = inFile.Read(binaryData, 0,
                                     (int)(inFile.get_Length()));
        inFile.Close();
    }
    catch (System.Exception exp) {
        // Error creating stream or reading from it.
        System.Console.WriteLine("{0}", exp.get_Message());
        return;
    }

    // Convert the binary input into Base64 UUEncoded output.
    // Each 3 byte sequence in the source data becomes a 4 byte
    // sequence in the character array. 
    long arrayLength = (long)(4.0 / 3.0 * binaryData.length);

    // If array length is not divisible by 4, go up to the next
    // multiple of 4.
    if (arrayLength % 4 != 0) {
        arrayLength += 4 - arrayLength % 4;
    }

    char base64CharArray[] = new char[(int)arrayLength];

    try {
        System.Convert.ToBase64CharArray(binaryData, 0, binaryData.length,
                                         base64CharArray, 0);
    }
    catch (System.ArgumentNullException exp) {
        System.Console.WriteLine("Binary data array is null.");
        return;
    }
    catch (System.ArgumentOutOfRangeException exp) {
        System.Console.WriteLine("Char Array is not large enough.");
        return;
    }

    // Write the UUEncoded version to the output file.
    System.IO.StreamWriter outFile;

    try    {
        outFile = new System.IO.StreamWriter(outputFileName, false,
                System.Text.Encoding.get_ASCII());
        outFile.Write(base64CharArray);
        outFile.Close();
    }
    catch (System.Exception exp) {
        // Error creating stream or writing to it.
        System.Console.WriteLine("{0}", exp.get_Message());
    }
} //EncodeWithCharArray

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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