string mysql ="select * from Table2 where date='+dateTimePicker1.Value+'";这句话有误
string mysql ="select * from Table2 where date='" + dateTimePicker1.Value.ToString() + "'";
string mysql ="select * from Table2 where date='" + dateTimePicker1.Value.ToString() + "'";
string mysql ="select * from Table2 where date='"+dateTimePicker1.Value+"'";
SqlConnection conn = new SqlConnection(connstr);
conn.Open();
SqlDataAdapter adp = new SqlDataAdapter(mysql, conn);
DataSet ds = new DataSet();
adp.Fill(ds, "Table2");
TimeSpan ts = dp.Subtract(dt);
string d = ds.Tables["Table2"].Rows[0][0].ToString();
string r = ds.Tables["Table2"].Rows[0][1].ToString();
string s = ds.Tables["Table2"].Rows[0][2].ToString();
string m = ds.Tables["Table2"].Rows[0][3].ToString();
MessageBox.Show(r);没有取得到数据所以数组下标越界
string mysql ="select * from Table2 where date=' "+dateTimePicker1.Value+"'"; SqlConnection conn = new SqlConnection(connstr);
conn.Open();
SqlDataAdapter adp = new SqlDataAdapter(mysql, conn);
DataSet ds = new DataSet();
adp.Fill(ds, "Table2");
TimeSpan ts = dp.Subtract(dt);
string d = ds.Tables["Table2"].Rows[0][0].ToString();
string r = ds.Tables["Table2"].Rows[0][1].ToString();
string s = ds.Tables["Table2"].Rows[0][2].ToString();
string m = ds.Tables["Table2"].Rows[0][3].ToString();
MessageBox.Show(r);查询数据库后,返回的数据为空
加个条件
if ds.Tables["Table2"].rows.count > 0Tables["Table2"]是空的啊.肯定会错.