protected void btDownLoad_Click(object sender, EventArgs e)

{

                  string _ID = "";

                foreach (GridViewRow gv in GridView1.Rows)

                {

                    CheckBox cb = (CheckBox)gv.FindControl("CheckBox1");

                    if (cb.Checked)

                    {

                        int index = gv.RowIndex;

                        DataKey key = this.GridView1.DataKeys[index];//获取主键

                        Int64 GVID = Convert.ToInt64(key.Values["ID"]);

                        _ID += GVID.ToString() + ",";

                    }

                }

                if (_ID == "")

                {

                    ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "click", "alert('请选择要下载的报告！')", true);

                }

                else

                {

                    int count = _ID.Split(',').Length - 1;

                    string[] AID = new string[count];

                    AID = _ID.Split(',');

                    for (int i = 0; i < count; i++)

                    {