Encoding::GetMaxCharCount Method
When overridden in a derived class, calculates the maximum number of characters produced by decoding the specified number of bytes.
Namespace: System.Text
Assembly: mscorlib (in mscorlib.dll)
Parameters
- byteCount
- Type: System::Int32
The number of bytes to decode.
Return Value
Type: System::Int32The maximum number of characters produced by decoding the specified number of bytes.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | byteCount is less than zero. |
| DecoderFallbackException | A fallback occurred (see Understanding Encodings for a complete explanation). |
To calculate the exact array size required by GetChars to store the resulting characters, the application should use GetCharCount. To calculate the maximum array size, it should use GetMaxCharCount. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.
GetMaxCharCount retrieves a worst-case number. If a fallback is chosen with a potentially large string, GetMaxCharCount retrieves 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 too small. You might also want to consider a different approach using GetCharCount or Decoder::Convert.
GetMaxCharCount has no relation to GetBytes. If your application needs a similar function to use with GetBytes, it should use GetMaxByteCount.
When using GetMaxCharCount, you should allocate the output buffer based on the maximum size of the input buffer. If the output buffer is constrained in size, you might use the Encoder::Convert(array<Char>, Int32, Int32, array<Byte>, Int32, Int32, Boolean, Int32%, Int32%, Boolean%) or Decoder::Convert(array<Byte>, Int32, Int32, array<Char>, Int32, Int32, Boolean, Int32%, Int32%, Boolean%) method instead.
Note that GetMaxCharCount considers the worst case for leftover bytes from a previous encoder operation. For most code pages, passing a value of 0 to this method retrieves values greater than or equal to 1.
Note: |
|---|
GetMaxCharCount(N) is not necessarily the same value as N* GetMaxCharCount(1). |
All Encoding implementations must guarantee that no buffer overflow exceptions occur if buffers are sized according to the results of this method's calculations.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
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