I think this may be a bug so I wanted to let you know about this.
I was trying to set up the SFListView with a Horizontal orientation and then set the span count within the Grid layout and was only getting a single row. I couldn't figure out what was happening until I did some testing. It looks like by setting both, the orientation is transposing how the layout is handled as it appears that setting GridLayout.SpanCount also sets the orientation to horizontal (IE they cancel each other out somehow)
To Replication this, get an item source of a few items and then use:
DBDinesh Babu Yadav Syncfusion Team May 3, 2019 01:59 AM
Thanks for using Syncfusion product.
We have checked the reported query with SpanCount and Orientation as Horizontal from our side. We would like to inform you that SfListView scrolls properly with horizontal orientation and SpanCount in our sample. We have attached the tested sample for your reference, please find the sample for your reference.
Can you please check with the above sample whether you are getting same issue our sample also. Meanwhile, please check whether you have defined any HeightRequest for SfListView. If no please revert us back with the issue replicated sample so that we could able to analyze the reported query better and provide appropriate solution at our end.