Visual Basic- Loop to make listbox update as checkbox is checked

Question

I'm having trouble having the listbox update as the checkbox is checked. I have a total of 8 "test_location" check boxes and I want the listbox to add items to "Steps_Queue_List" and store "1" in the "Test_Locations" array when the location is checked. Also want to clear the list when the checkbox is unchecked. This works so far but I would much prefer to learn how to make a loop for this:

Private Sub Location_CheckBox_1_CheckedChanged(sender As Object, e As EventArgs) Handles Location_CheckBox_1.CheckedChanged
    If Location_CheckBox_1.Checked Then
        Test_Locations(0) = 1
        Steps_Queue_List.Items.Add("test for location" & 1, 1)

    ElseIf Location_CheckBox_1.Checked = False Then
        Test_Locations(0) = 0
        Steps_Queue_List.Items.RemoveAt(0)
    End If
End Sub

Private Sub Location_CheckBox_2_CheckedChanged(sender As Object, e As EventArgs) Handles Location_CheckBox_2.CheckedChanged
    If Location_CheckBox_2.Checked Then
        Test_Locations(1) = 1
        Steps_Queue_List.Items.Add("test for location" & 2, 2)

    ElseIf Location_CheckBox_2.Checked = False Then
        Test_Locations(1) = 0
        Steps_Queue_List.Items.RemoveAt(0)
    End If
End Sub

Private Sub Location_CheckBox_3_CheckedChanged(sender As Object, e As EventArgs) Handles Location_CheckBox_3.CheckedChanged
    If Location_CheckBox_3.Checked Then
        Test_Locations(2) = 1
        Steps_Queue_List.Items.Add("test for location" & 3, 3)

    ElseIf Location_CheckBox_3.Checked = False Then
        Test_Locations(2) = 0
        Steps_Queue_List.Items.RemoveAt(0)
    End If
End Sub

Thanks in advance.

Why is this tagged VB6?

StayOnTarget
– StayOnTarget

2017-08-22 11:13:57 +00:00
Commented Aug 22, 2017 at 11:13 — StayOnTarget
– StayOnTarget, Commented Aug 22, 2017 at 11:13

Steve · Accepted Answer · 2017-08-21 17:58:20Z

1

You don't need a loop but you can just handle everything in a single method.

Set the property Tag of your Checkboxes to a progressive value starting from 1 to 8 matching the text value you want to be displayed in the listboxes.

Then setup an event handler that manages all the CheckBoxChanged events for all the CheckBox.

In this event handler retrieve the tag and use it to address the array index and the listbox to update

' Handle all Checkbox changed with the same handler
Private Sub OnCheckBoxChanged(sender As Object, e As EventArgs) 
Handles Location_CheckBox_1.CheckedChanged,Location_CheckBox_2.CheckedChanged,
        Location_CheckBox_3.CheckedChanged,Location_CheckBox_4.CheckedChanged,
        Location_CheckBox_5.CheckedChanged,Location_CheckBox_6.CheckedChanged,
        Location_CheckBox_7.CheckedChanged,Location_CheckBox_8.CheckedChanged

    ' Discover which checkbox has been clicked
    Dim chk = DirectCast(sender, CheckBox)

    ' Now read the value of the Tag property of that checkbox
    Dim idx = Convert.ToInt32(chk.Tag)
    If chk.Checked Then
        Test_Locations(idx - 1) = 1
        Steps_Queue_List.Items.Add("test for location" & idx, idx)
    Else
        Test_Locations(idx - 1) = 0
        Steps_Queue_List.Items.RemoveAt(0)
    End If
End Sub

edited Aug 21, 2017 at 17:58

answered Aug 21, 2017 at 16:56

Steve

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4 Comments

phillip87 Over a year ago

Thank you Steve. What does this do?: Dim idx = Convert.ToInt32(chk.Tag) looks like it is only storing "0" for all checkboxes

Steve Over a year ago

If you set the Tag property to 1,2,3,4,5,6,7,8 for your eight checkboxes this should return the integer from the object Tag property and you can use this number to address the index of the Test_Locations array and write the appropriate item in the listbox.

Steve Over a year ago

Please recheck the code, removed a weird Then after the Else

phillip87 Over a year ago

Gotcha. yes, I removed the "then" when I ran it. Thanks so much! I didn't know you can "tag" the checkboxes. Working great now.

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