Checkbox selection check and loop through the checkboxlist ,asp.net /c#

 //.aspx code

 <asp:CheckBoxList runat="server"  RepeatColumns="0" Height="250" Width="150"  RepeatDirection="Vertical"
                                                   CssClass="btext" ID="chkLstSkill">
                                               </asp:CheckBoxList>

//.cs code
 string values = "";
if (chkLstSkill.SelectedValue = = "")
                {
       //do something if not selected          
}
else
{

  // We perform a for loop to check if each checkbox is selected then we get the value
                    foreach (ListItem objItem in chkLstSkill.Items)
                    {
                        if (objItem.Selected)
                        {
                            values += objItem.Value;
                            TrainingID = values;
                        
             //Use below if u want only one id at a time else dont use it
              //       values = "";
                //    TrainingID = ""; //
                  
                        }

}