UnicodeEncoding.GetMaxByteCount(Int32) Method

Definition

Calculates the maximum number of bytes produced by encoding the specified number of characters.

public:
 override int GetMaxByteCount(int charCount);
public override int GetMaxByteCount (int charCount);
override this.GetMaxByteCount : int -> int
Public Overrides Function GetMaxByteCount (charCount As Integer) As Integer

Parameters

charCount
Int32

The number of characters to encode.

Returns

The maximum number of bytes produced by encoding the specified number of characters.

Exceptions

charCount is less than zero.

-or-

The resulting number of bytes is greater than the maximum number that can be returned as an integer.

A fallback occurred (for more information, see Character Encoding in .NET)

-and-

EncoderFallback is set to EncoderExceptionFallback.

Examples

The following example demonstrates how to use the GetMaxByteCount method to return the maximum number of bytes required to encode a specified number of characters.

using namespace System;
using namespace System::Text;
int main()
{
   UnicodeEncoding^ Unicode = gcnew UnicodeEncoding;
   int charCount = 2;
   int maxByteCount = Unicode->GetMaxByteCount( charCount );
   Console::WriteLine( "Maximum of {0} bytes needed to encode {1} characters.", maxByteCount, charCount );
}

using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {
        UnicodeEncoding Unicode = new UnicodeEncoding();
        int charCount = 2;
        int maxByteCount = Unicode.GetMaxByteCount(charCount);
        Console.WriteLine(
            "Maximum of {0} bytes needed to encode {1} characters.",
            maxByteCount,
            charCount
        );
    }
}
Imports System.Text

Class UnicodeEncodingExample
    
    Public Shared Sub Main()
        Dim uni As New UnicodeEncoding()
        Dim charCount As Integer = 2
        Dim maxByteCount As Integer = uni.GetMaxByteCount(charCount)
        Console.WriteLine("Maximum of {0} bytes needed to encode {1} characters.", maxByteCount, charCount)
    End Sub
End Class

Remarks

To calculate the exact array size required by GetBytes to store the resulting bytes, the application uses GetByteCount. To calculate the maximum array size, the application should use GetMaxByteCount. The GetByteCount method generally allocates less memory, while the GetMaxByteCount method generally executes faster.

GetMaxByteCount retrieves a worst-case number, including the worst case for the currently selected EncoderFallback. If a fallback is chosen with a potentially large string, GetMaxByteCount can return large values.

In most cases, this method retrieves reasonable numbers for small strings. For large strings, you might have to choose between using very large buffers and catching errors in the rare case that a more reasonable buffer is exceeded. You might also want to consider a different approach using GetByteCount or Encoder.Convert.

GetMaxByteCount has no relation to GetChars. If your application needs a similar function to use with GetChars, it should use GetMaxCharCount.

Note

GetMaxByteCount(N) is not necessarily the same value as N* GetMaxByteCount(1).

Applies to

See also