Show dataset parameters in Azure Synapse Dataflow

Case
I have a parameterized dataset. The parameter is showing in the pipeline's Copy Data Activity, but it's not showing in the Synappse (or ADF) dataflow under source or sink. When going the the Data preview it shows me an error message: No value provided for Parameter 'MyFileName'.

No value provided for Parameter 'abc'

Solution
You added a parameter to your dataset so you can for example use it in a foreach construction in your pipeline.

Dataset with parameter

In your pipeline's Copy Data Activity you can see the dataset parameter as soon as you select your dataset with the parameter.

Parameter showing in Copy Data Activity

However when you select that same dataset as a source (or sink) you won't see the parameter appearing in the editor. On this screen there is no way to provide the parameter and when you debug the source you will get an error stating that you need to provide a value for that parameter: No value provided for Parameter 'MyFileName'.

Dataset selected, but no parameter

The first option is to provide a default value for your dataset parameter in the dataset itself. Now you won't get that error. This is perhaps in some cases suitable, but for most cases it isn't.

Default value for parameter in dataset

Now go to your pipeline and add a Dataflow Activity for your Dataflow. You will see the Parameter appear in the settings tab (not in the Parameters tab which is for Dataflow parameters only). This is handy for when you when want to debug the Pipeline and Dataflow at the same time, but not for when you just want to debug your Dataflow to see the data preview.

Parameter is back again

Now go to your Dataflow and click on Debug Settings. Whitin the Debug Settings go to the Parameters tab. Find your source under Dataset parameters and provide a value for debugging.

Provide Value for parameter in Dataflow Debug Settings

Go to your source (or sink) in the Dataflow and then go to Data preview to see the actual data.

There is data in our preview

Conclusion

In this post you learned how to debug your Dataflow when using a parameterized Dataset. Compared to other parts of Synapse (or ADF) it would probably make more sense to first create a Dataflow Parameter (with a default value for debugging). Then show the Dataset Parameter it in the Source (or Sink) settings page where you override it with the Dataflow Parameter.