This app contains 3 tabitems.
The first tabitem titled Dashboard basically shows some filtered data in a datagrid from the billdata table of the database,
The second tabitem titled Forwarding mainly has a combo box, couple of buttons (Search and Export2DOCX) and couple of datagrid's (billsGrid and adjGrid).
The third tabitem titled Report also has a combo box, a datagrid and some buttons, text box's, radio buttons etc.

All the datagrid's have different ICollectionView's (tabitem1 => PendingBills, tabitem2 => FilteredBills, AdjBills and tabitem3 =>  AllBills) as their ItemsSource's.
When the app is launched both the combo box's get the list of uniques items of the Party column from table billdata as its ItemsSource (ComboItems and ComboItems2).
In second tabitem, when the user select's an item (SelectedCBItem) from the combo box and hits the search button then the app checks the billdata table whose Party column
data have the same value as SelectedCBItem and also whose Remarks column is empty or null and displays them in the first datagrid and checks the cndndata table whose Vendor column
data have the same value as SelectedCBItem and checks for UsedOn column to be empty or null and displays it in the second datagrid(if any data found).
Then when atleast one item from the first datagrid is selected and the Export2DOCX is hit it would generate a word document(code not added to keep it less confusing) and update
the selected row/rows Remarks and PaidOn column for billdata table and UsedOn column for cndndata table (if any, when the 2nd datagrid items are also selected).

In the third tabitem, when an item is selected (SelectedCBItem2) from the combo box the datagrid in this tabitem displays all items found in the billdata table whose
Party column match with SelectedCBItem2. Further filtering can be done using the radiobuttons, text box and the button titled GO.
When an item from the datagrid in third tabitem is selected a CRUD form with multiple text box's, Datepicker's and Add, Delete, Save and Cancel button appears to perform CRUD operations.