HOWTO: Enable Trace Logging in DotTwain

DotTwain has tracing code added to it in order to help us debug a problem. You can enable tracing by adding an Application Configuration File (app.config) to your project. Then add the following code to create a TraceSwitch named "Atalasoft.Twain".

<configuration>
    <system.diagnostics>
        <switches>
            <add name="Atalasoft.Twain" value="4" />
        </switches>
        <trace autoflush="true" indentsize="4">
            <listeners>
                <add name="DotTwainListener" type="System.Diagnostics.TextWriterTraceListener" initializeData="c:\users\YOUR_USERNAME\Documents\DotTwain.log" />
            </listeners>
        </trace>
    </system.diagnostics>
</configuration>

When you run your project, the DotTwain trace information will be listed in the Output - Debug window within Visual Studio. The above code also creates a listener that will output the trace information to a log file (c:\users\YOUR_USERNAME\Documents\DotTwain.log).

IMPORTANT: set the InitializeData path to a location that the user running the app has full write access to and make sure the folder exists. This article used to say c:\DotTwain.log but we found that direct writing to the root of the C drive failed for non administrative users.

Please consider creating a directory under your profile then providing the full path to that such as

c:\users\YOUR_USERNAME\Documents\DotTwain.log

If no log is written, try running the application as administrator... and make sure the path defined exists and is writable

You can learn more about tracing from MSDN: https://docs.microsoft.com/en-us/dotnet/framework/debug-trace-profile/how-to-create-initialize-and-configure-trace-switches

Original Article:

Q10027 - HOWTO: Enable Trace Logging in DotTwain