Inlining Syntax Error Messages into Templates

By default, LINQ Reporting Engine throws an exception when encounters a template syntax error. Such an exception provides information on a reason of the error and specifies a tag or expression part where the error is encountered. In most cases, this information is enough to find a place in a template causing the error and fix it.

However, when dealing with complex templates containing a large number of tags, it becomes harder to find an exact place in a template causing an error. To make things easier, the engine supports the ReportBuildOptions.INLINE_ERROR_MESSAGES option that enables inlining of a syntax error message into a template document at an exact position where the error occurs during runtime.

Note – A template syntax error message is written using a bold font to make it more apparent.

Consider the following template.

<<var [name]>>

By default, such a template causes the engine to throw an exception while building a report. However, when ReportBuildOptions.INLINE_ERROR_MESSAGES is applied, no exception is thrown and the report looks as follows then.

<<var [name] Error! An assignment operator is expected. >>

Note – Only messages describing errors in template syntax can be inlined; messages describing errors encountered during expressions’ evaluation cannot.

When ReportBuildOptions.INLINE_ERROR_MESSAGES is applied, a Boolean value returned by a ReportingEngine.buildReport overload indicates whether building of a report was finished successfully or was interrupted because of a template syntax error. This enables you to process reports which building succeeded or failed differently as shown in the following code snippet.

ReportingEngine engine = new ReportingEngine();
engine.setOptions(ReportBuildOptions.INLINE_ERROR_MESSAGES);

if (engine.buildReport(...))
{
	// Do something with a successfully built report.
}
else
{
	// Do something with a report containing a template syntax error.
}

Note – When ReportBuildOptions.INLINE_ERROR_MESSAGES is not applied, ReportingEngine.buildReport overloads return true if there were no template syntax errors encountered or throw an exception otherwise.

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FAQ

1. Q: How do I enable inline syntax error messages for a report?
   A: Create a ReportingEngine instance and set its options to ReportBuildOptions.INLINE_ERROR_MESSAGES before calling buildReport. This tells the engine to embed syntax error messages directly into the generated document instead of throwing an exception.

2. Q: What does the boolean result of buildReport indicate when inline error messages are enabled?
   A: The method returns true if the report was built without any template‑syntax errors. It returns false when a syntax error was detected and inlined into the document, allowing you to handle the two cases separately.

3. Q: Are runtime evaluation errors (e.g., division by zero) also inlined with this option?
   A: No. Only syntax‑related errors are inlined. Errors that occur while evaluating expressions are still thrown as exceptions because they cannot be represented as inline messages.

4. Q: Can I change the appearance (font, color) of the inlined error messages?
   A: The engine writes error messages using a bold font by default. Custom styling is not configurable through the API; you would need to post‑process the document to modify the formatting after the report is generated.

5. Q: Does enabling INLINE_ERROR_MESSAGES suppress all exceptions from the reporting engine?
   A: It suppresses exceptions that are caused by template syntax errors only. Other exceptions (e.g., I/O errors, missing data sources) are still thrown and must be handled in the usual way.