How so simplify Switch Case and if stement?

I am using that switch case to select the index of the foreach, and using and if statement to increment model.Hours1(2,3,4,5...) but know I want to do this for hours100. How can i do?

switch (colNames.IndexOf(item2))
{
    case 0:
        if (model.Hours == null)
        {
            item.Hours = 0;
        }
        else
        {
            item.Hours = (decimal)model.Hours;
            item.Hours_Remaining = (decimal)model.Hours;
        }
        break;

    case 1:
        if (model.Hours1 == null)
        {
            item.Hours = 0;
        }
        else
        {
            item.Hours = (decimal)model.Hours1;
            item.Hours_Remaining = (decimal)model.Hours;
        }
        break;
}