private void DC_Add_Load(object sender, EventArgs e)
{
Coures_Dal cd = new Coures_Dal();
List <Coures> lc = new List <Coures>();
comboBox1.DataSource = cd.QueryCouresAll();
comboBox1.DisplayMember = "C_NAME";
comboBox1.Text = "请选择单词包类型";
}