Inserting Documents Dynamically

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You can insert contents of outer documents to your reports dynamically using doc tags. A doc tag denotes a placeholder within a template for a document to be inserted during runtime.

Syntax of a doc tag is defined as follows.

<<doc [document_expression]>>

Note – A doc tag can be used almost anywhere in a template document except textboxes and charts.

An expression declared within a doc tag is used by the engine to load a document to be inserted during runtime. The expression must return a value of one of the following types:

  • A byte array containing document data
  • A Stream instance able to read document data
  • An instance of the Document class
  • A string containing a document URI, path, or Base64-encoded document data

While building a report, an expression declared within a doc tag is evaluated and its result is used to load a document which content replaces the doc tag then.

Note – If an expression declared within a doc tag returns a stream object, then the stream is closed by the engine as soon as a corresponding document is loaded.

By default, while inserting content of an outer document, the engine applies corresponding styles of a template document. This makes content of a result document look more consistent. However, you can keep source formatting for content being inserted by using a sourceStyles switch as shown in the following snippet.

<<doc [document_expression] -sourceStyles>>

The engine exhibits similar behavior when dealing with list numbering. By default, numbered lists from a template document are continued when their identifiers match those from a document being inserted. However, if numbering for content being inserted should be separated and kept as is, this can be done by applying a sourceNumbering switch as follows.

<<doc [document_expression] -sourceNumbering>>

Also, you can trim the last paragraph break from a document being inserted by using an inline switch. In particular, this feature is useful for a single-paragraph document being inserted, when it is necessary to put the document’s content within the same paragraph that contains a corresponding doc tag in order to apply the paragraph’s formatting such as list numbering. The following snippet shows the template syntax for this.

<<doc [document_expression] -inline>>

By default, a document being inserted is not checked against template syntax and is not populated with data. However, you can enable this by using a build switch as follows.

<<doc [document_expression] -build>>

When a build switch is used, the engine treats a document being inserted as a template that can access the following data available at the scope of a corresponding doc tag:

  • Data sources
  • Variables
  • A contextual object (see “Using Contextual Object Member Access” for more information)
  • Known external types (see “Setting up Known External Types” for more information)