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Processing Instructions in the XML Assembler Pipeline Component

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Processing instructions provide information to the application that processes an XML document. Such information may include instructions about how to process the document, how to display it, and so on.

Processing instructions are added to an XML document by the Add processing instructions property (or the equivalent XMLNorm.ProcessingInstructionOption property on the message context). Processing instruction text is specified with the Add processing instructions text property (or the equivalent XMLNorm.ProcessingInstruction property on the message context).

The Add processing instructions property (or XMLNorm.ProcessingInstructionOption property) has three possible values, which are described in the following table.

Value Value Description
Append 0 New processing instructions from the XML Assembler are appended to the processing instructions at the beginning of the document.
Create new 1 New processing instructions from the XML Assembler overwrite existing processing instructions at the beginning of the document.
Ignore 2 Processing instructions at the beginning of the document are removed.

The pair of processing instructions (or message context properties) specified on a message context take precedence over the property pair specified in Pipeline Designer. For example, if XMLNorm.ProcessingInstructionOption is specified as Create new (1) and XMLNorm.ProcessingInstruction is not specified, an empty processing instruction will replace an existing processing instruction.

As another example, if XMLNorm.ProcessingInstruction is specified but XMLNorm.ProcessingInstructionOption is not, none of the properties from the message context are used. In this case, the processing instructions from Pipeline Designer are used.

By default, Add processing instructions is set to Append, and Add processing instructions text is empty.

Processing Properties and Envelopes

Because processing instructions are not preserved for the envelopes, the following combination of flat file assembler settings results in only the outermost envelope having the processing instruction:

  • Processing instruction scope property set to "Envelope."

  • Add processing instructions property set to "Append."

    The envelope would use the processing instruction specified in the assembler's Add Processing instructions text property.

    Any existing processing instructions in either the outer or inner envelope(s), as specified in the incoming message, will not be present in the output message(s).

See Also

XML Assembler Pipeline Component
How to Configure the XML Assembler Pipeline Component
Pipelines-AssemblerDisassembler (BizTalk Server Samples Folder)