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HttpUtility.UrlDecode Method (Byte[], Int32, Int32, Encoding)

Converts a URL-encoded byte array into a decoded string using the specified encoding object, starting at the specified position in the array, and continuing for the specified number of bytes.

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

public static string UrlDecode(
	byte[] bytes,
	int offset,
	int count,
	Encoding e


Type: System.Byte[]

The array of bytes to decode.

Type: System.Int32

The position in the byte to begin decoding.

Type: System.Int32

The number of bytes to decode.

Type: System.Text.Encoding

The Encoding object that specifies the decoding scheme.

Return Value

Type: System.String
A decoded string.


bytes is null, but count does not equal 0.


offset is less than 0 or greater than the length of the bytes array.

- or -

count is less than 0, or count + offset is greater than the length of the bytes array.

If characters such as blanks and punctuation are passed in an HTTP stream, they might be misinterpreted at the receiving end. URL encoding converts characters that are not allowed in a URL into character-entity equivalents; URL decoding reverses the encoding. For example, when embedded in a block of text to be transmitted in a URL the characters < and > are encoded as %3c and %3e.

To encode or decode values outside of a web application, use the WebUtility class.

.NET Framework

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

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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