When one of the toolbar button's is clicked, the buttonclick event is raised. Via the ToolBarButtonClickEventArgs parameter, you are able to interogate the button property to determine which button was selected. Here is one way that determines the button in question using the equals() method. This method checks the equality by comparing object references:
Code:
private void toolBar1_ButtonClick(object sender, System.Windows.Forms.ToolBarButtonClickEventArgs e) {
if (e.Button.Equals(this.btnAdd)) {
MessageBox.Show("Add Clicked");
}else {
MessageBox.Show("Remove Clicked");
}
}