LINQ query to filter a list returns nothing

Question

Following a tutorial, i've built a LINQ query to filter a List of objects:
Dim Query = From FilteredItem In Items, FiltSupp In FilteredItem.Suppliers Where ((SuppliersComboBox.SelectedItem.ToString = "All Suppliers" OrElse FiltSupp.CompanyName = SelectedSupplier) And (String.IsNullOrEmpty(TxtItemCode.Text) OrElse FilteredItem.ItemCode.ToString.Contains(TxtItemCode.Text)) And (String.IsNullOrEmpty(TxtName.Text) OrElse FilteredItem.Name.ToLower.Contains(TxtName.Text.ToLower)) And (String.IsNullOrEmpty(TxtPkgCost.Text) OrElse FilteredItem.PkgCost.ToString.Contains(TxtPkgCost.Text))) Select FilteredItem

The problem is that the query returns nothing even when the list is being populated.
At debugging, the list value is correct (populated with few items), but the query doesn't returning anything. I can't figure out what is wrong, so any suggestion would be greatly appreciated!
Ps. I'm using vb.net, but answers in C# are also wellcome

Answer 1

To start off with, this answer is obviously not complete yet, so please hold off any downvotes until I finalize it. I have every intention of helping the OP if I can, however at this time there is no way for me to even begin helping out because the information needed is not present.

@ISAE, Can you please provide the following:

• hoping the Items being queried is a strongly typed DataTable; the class file for the Items object type, preferably the designer files also (.xsc, .xsd, and .xss)
• the forms' designer files and code behinds.

Alternatively, if the project can be put on GitHub, that would be even better. If you can't release all of that code, then really need to know enough to somewhat reconstruct what's going on. As one of the comments pointed out, that LINQ query is really messy and it's hard to dissect right now.