Keep track clicks on button in another form

[sinjok]

I'm working on a project which has 4 combo boxes.
Each of them has a drop down list of numbers from 0 to 9.

How do I validate if each combo box is selected with one number when I click on a button?

Is validating a checkbox the same way as validating combo box?

Thank you.

[Hack]

If something in the combo is selected, it will be in its text property so you could check to see whether that is empty or not.

Checkboxes have a "Checked" property

If CheckBox1.Checked = True Then
      MessageBox.Show("checked")
Else
      MessageBox.Show("unchecked")
End If

[stanav]

On form load, you set the combobox.selectedIndex property of all 4 comboboxes to -1.
In your button click event handler, you read the combobox.selectedindex of the 4 above mentioned comboboxes, and if any of them is < 0, that combobox is not yet selected by the user.

[sinjok]

On form load, you set the combobox.selectedIndex property of all 4 comboboxes to -1.
In your button click event handler, you read the combobox.selectedindex of the 4 above mentioned comboboxes, and if any of them is < 0, that combobox is not yet selected by the user.

Thanks for your reply.

I have another question: For a lottery program, I like to keep track how many the user has played the game.
The main form where the user needs to click on a button called "PLAY" to proceed the game.
I have another new form that will keep track numbers of game he/she has played (I'd like to show the numbers of game in a label).