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ASCIIEncoding.GetMaxCharCount Method

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

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

Public Overrides Function GetMaxCharCount ( _
	byteCount As Integer _
) As Integer


Type: System.Int32

The number of bytes to decode.

Return Value

Type: System.Int32
The maximum number of characters produced by decoding the specified number of bytes.


byteCount is less than zero.


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

The GetCharCount method calculates the exact array size required by the GetChars method to store the resulting characters, whereas the GetMaxCharCount method calculates the maximum array size. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.

GetMaxCharCount retrieves a worst-case number, including the worst case for the currently selected DecoderFallback. If a decoder fallback is present that has a maximum fallback length of n, the GetMaxCharCount method returns n * byteCount.

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


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

The following example demonstrates how to use the GetMaxCharCount method to calculate the maximum number of characters needed to decode a specified number of bytes.

Imports System
Imports System.Text

Class ASCIIEncodingExample
    Public Shared Sub Main()
        Dim ascii As New ASCIIEncoding()
        Dim byteCount As Integer = 8
        Dim maxCharCount As Integer = ascii.GetMaxCharCount(byteCount)
        Console.WriteLine( _
            "Maximum of {0} characters needed to decode {1} bytes.", _
            maxCharCount, _
            byteCount _
    End Sub 
End Class

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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