Change button color?

1

I’ve spent ages trying to work this problem out… When I click on a button the background should change colour. If another button has already been clicked previously (btnSkillSelected = true) then this button should first be turned back transparent. This does not however happen, instead it stays light blue!


// When a btn is checked the following method is executed
private void btnSkill_CheckedChanged(object sender, EventArgs e)
{
// If a btn has been enabled before
if (btnSkillSelected == false)
{
MessageBox("1st time a btn is selected!");
// save selected btnSkill
selectedSkillID = int.Parse(btnSkill.ID);
}
else
{
MessageBox("not the 1st time a btn is selected!");
// Find the previously selected btn
for (int i = 0; i < criterium.Length; i++)
{
if (btnSkill.ID == Convert.ToString(selectedSkillID))
{
// Disable the previously selected button
btnSkill.BackColor = System.Drawing.Color.Transparent;
btnSkill.Enabled = true;
}
}
}
// True for both methods:
// Show that a button has been enabled
btnSkillSelected = true;
// Change state of currently selected btn
btnSkill = (Button)sender;
selectedSkillID = int.Parse(btnSkill.ID); 
btnSkill.BackColor = System.Drawing.Color.LightBlue;
btnSkill.Enabled = false;
// Create side table
CreateTblCriterium(selectedSkillID);
}