Missing DLLs in Creating MSI Installer

Updated:September 23, 2025

When creating an MSI installer, you may encounter the following exception:

2025-01-27 16:57:23 - Error: IronBarCodeDetection.Exceptions.IronBarcodeDetectionException: Unexpected error occurred during execution of the IronBarcode Machine Learning library. Please provide details to support@ironsoftware.com for a resolution. ---> System.TypeInitializationException: The type initializer for 'Microsoft.ML.OnnxRuntime.NativeMethods' threw an exception. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.ML.OnnxRuntime.NativeMethods..cctor()
   --- End of inner exception stack trace ---
   at Microsoft.ML.OnnxRuntime.SessionOptions..ctor()
   at Iron.BarCode.Extensions.xjtagg`1..ctor(Stream dfepdx, SessionOptions dfepdy)
   at IronBarCodeDetection.BarcodeDetect.PredictObject[TModel](Stream modelStream)
   --- End of inner exception stack trace ---
   at IronBarCodeDetection.BarcodeDetect.PredictObject[TModel](Stream modelStream)
   at IronBarCodeDetection.BarcodeDetect.DetectBarCode()
   at Iron.BarCode.Extensions.cuewjf.ehxbbs(BarcodeDetect tlxjvd)
   at Iron.BarCode.Extensions.cuewjf.ehxbbr(AnyBitmap tlxjvd, Double tlxjve)
   at Iron.BarCode.Extensions.cuewjo.mvanli(AnyBitmap tlxjvd, Double tlxjve)
   at Iron.BarCode.Extensions.cuewjo.mvanlf(Image`1 tlxjvd)
   at Iron.BarCode.Extensions.cuewjo.mvankh(Object tlxjvd)
   at IronBarCode.BarcodeReader.Read(AnyBitmap inputImage, BarcodeReaderOptions barcodeReaderOptions)
   at WindowsFormsBarcode.Form1.btnBrowse_Click_1(Object sender, EventArgs e)
2025-01-27 16:57:23 - Error Message: Unexpected error occurred during execution of the IronBarcode Machine Learning library. Please provide details to support@ironsoftware.com for a resolution.
2025-01-27 16:57:23 - Inner Exception: The type initializer for 'Microsoft.ML.OnnxRuntime.NativeMethods' threw an exception.
2025-01-27 16:57:23 - Inner Exception Stack Trace:    at Microsoft.ML.OnnxRuntime.SessionOptions..ctor()
   at Iron.BarCode.Extensions.xjtagg`1..ctor(Stream dfepdx, SessionOptions dfepdy)
   at IronBarCodeDetection.BarcodeDetect.PredictObject[TModel](Stream modelStream)

Reason

This error occurs because the library cannot find the required files to function properly.

Solution

To ensure the MSI installer runs smoothly, you must include the following three files in your setup project: onnxruntime.dll, IronBarcodeInterop.dll, and ReaderInterop.dll. These files are generated when you build the project in Release mode:

onnxruntime.dll: Located at MsiInstallerSample\MsiInstallerSample\bin\Release
IronBarcodeInterop.dll: Located at MsiInstallerSample\MsiInstallerSample\bin\Release\runtimes\win-x86\native
ReaderInterop.dll: Located at MsiInstallerSample\MsiInstallerSample\bin\Release\runtimes\win-x86\native

Make sure all three files are added to your Setup Project to avoid this exception.

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.