IListSource 不包含任何数据源。

[zhengchengbaishi]

string xibie = DropDownList1.SelectedValue;

string zhrscore;
TextBox tb = (TextBox)GridView1.Rows[0].Cells[3].FindControl("TextBox1");
zhrscore = tb.Text;

SqlConnection SqlCon = new SqlConnection(ConfigurationManager.AppSettings["SqlConString"]);
string str = "update jieguo set zhrscore='" + zhrscore + "' where dept='" + xibie + "'";
SqlCon.Open();
SqlDataAdapter myda = new SqlDataAdapter(str,SqlCon);
//SqlCommand SqlCmd = new SqlCommand(str,SqlCon);
DataSet myds = new DataSet();
myda.Fill(myds,"jieguo");
//SqlCmd.ExecuteNonQuery();
GridView1.DataSource = myds;
GridView1.DataBind();//此处错误提示：IListSource 不包含任何数据源
SqlCon.Close();

[zhengchengbaishi]

没人能解决吗？