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.InlineErrorMessages 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.InlineErrorMessages 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.InlineErrorMessages 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.Options |= ReportBuildOptions.InlineErrorMessages;
if (engine.BuildReport(...))
{
	// Do something with a successfully built report.
}
else
{
	// Do something with a report containing a template syntax error.
}

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