DropDownList选择某个值确定在datagrid中显示数据

DropDownList选择某个值后，点击确定按钮，然后根据选的这个值在datagrid显示数据库相关数据
我的代码如下：private void Btn_ok_Click(object sender, System.EventArgs e)

{
    string strconn = ConfigurationSettings.AppSettings["ConnectionString"];
    cn = new SqlConnection(strconn);
    SqlCommand cm = new SqlCommand("line", cn);
    cm.CommandType = CommandType.StoredProcedure;

    cm.Parameters.Add(new SqlParameter("@day", SqlDbType.VarChar, 8));

    cm.Parameters["@day"].Value = Ddl_kind.SelectedValue.ToString();

    try
    {
        SqlDataAdapter myAdapter = new SqlDataAdapter();

        myAdapter.SelectCommand = cm;

        DataSet ds = new DataSet();

        myAdapter.Fill(ds);
        datagrid1.DataSource = ds;
        datagrid1.DataBind();

    }
    catch
    { }

}
    请问哪里有问题