UTF8Encoding.GetMaxCharCount Method (Int32)

 
System_CAPS_noteNote

The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

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

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

public override int GetMaxCharCount(
	int byteCount
)

Parameters

byteCount
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.

Exception Condition
ArgumentOutOfRangeException

byteCount is less than zero.

-or-

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

DecoderFallbackException

A fallback occurred (see Character Encoding in the .NET Framework for complete explanation)

-and-

DecoderFallback is set to DecoderExceptionFallback.

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

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

In most cases, this method returns 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 GetCharCount or Encoder.Convert.

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

System_CAPS_noteNote

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

The following example uses the GetMaxCharCount method to return the maximum number of characters produced by decoding a specified number of bytes.

using System;
using System.Text;

class UTF8EncodingExample {
    public static void Main() {
        UTF8Encoding utf8 = new UTF8Encoding();
        int byteCount = 8;
        int maxCharCount = utf8.GetMaxCharCount(byteCount);
        Console.WriteLine(
            "Maximum of {0} characters needed to decode {1} bytes.",
            maxCharCount,
            byteCount
        );
    }
}

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top
Show: