Using VB.net and excel (combo box & search)

New to programming and need to make a program in VB to interact with the Excel in the background

The Idea is to have two combo boxes, one "country", the other "city" (If country chosen, list of cities would be reduced to that country; if city is chosen, country would be selected automatically);

I have a DataGridView which displays two columns from the excel speadsheet, the person's fist name and the last name.

So given the city or a country/city a list of people would be displayed living in that country.

Also I'm trying to make a searchbox, whereby when you type into a textfield, given what you have typed so far it would filter the first name (containing what you have typed) in the GridView.

So far I have managed to get other things working, such as radiobuttons and checkboxes with different options.

I could not find anything that would work in regards to the comboboxes and the search field (without a button, so "live" filtering process would need to take place).

I am comfortable with SQL so I've been using sql so far to send queries to the excel and retrieve info for the grid view.

Could you please help? (may be provide with the template of how I should code it....)

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I am using Visual Basic 2012 and OleDB 4.0 (If i'm not mistaken) to make the connection.