Export to HTML/MHTML fails when using SSRS local report viewer control

Question

We are using the local Report Viewer control in SSRS v14 to render a report to HTML/MHTML using the Render method on the Microsoft.Reporting.WebForms.LocalReport object.

We also tried exporting to MHTML format (see https://learn.microsoft.com/en-us/sql/reporting-services/mhtml-device-information-settings?view=sql-server-ver15) but this failed with the error "Specified argument was out of the range of valid values.". Below is the DeviceInfo used for the Render method:

Dim deviceInfo As String = "<DeviceInfo>" &
"<OutputFormat>MHTML</OutputFormat>" &
"JavaScript" & False & "</JavaScript>" &
"<OutlookCompat>" & True & "</OutlookCompat>" &
"<DataVisualizationFitSizing>" & "Approximate" & "</DataVisualizationFitSizing>" &
"</DeviceInfo>"

Are HTML/MHTML export formats supported with the local Report Viewer control and, if so, does anyone have a solution to this problem? We are looking for a supported and documented API, not a hack or workaround. Thank you in advance.

Answer 1

Hi @SoftwareUser ,
Unlike the Report Server the ReportViewer control does not connect to databases or execute queries. Also, in local mode the only export formats available are Excel, Word and PDF. (In remote mode all formats supported by the Report Server are available.) The ReportViewer control cannot be extended by adding custom renderers or custom report items.
If you want to export reports to HTML/MHTML in native mode ReportViewer, you can consider using Aspose.Words for Reporting Services.
Best Regards,
Joy

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