在datetimepicker中选择日期时，值不会显示在datagridview中

Question

当我选择From Date和Todate from datetimepicker来显示datagridview中的数据时，datagridview显示空数据，代码写入按钮点击evet，这里我使用访问数据库

DateTime startT = new DateTime();
                DateTime endT = new DateTime();
                startT = dateTimePicker1.Value.Date;
                endT = dateTimePicker2.Value.Date;
                if (startT.Date > endT.Date)
                {
                    MessageBox.Show("To Date Cannot be greater than Start Date");
                }
                else
                {
                    string connetionString = null;
                    connetionString = ConfigurationManager.ConnectionStrings["AccessConnectionString"].ConnectionString;
                    con.ConnectionString = connetionString;

                    DataSet ds = new DataSet();
                    string sql = "SELECT Medicine_name,sum(Medicine_count) as Medicine_count,To_Date from Medicine_count_info where [To_Date] Between #" + startT.ToString("dd'/'MM'/'yyyy") + "#And #" + endT.ToString("dd'/'MM'/'yyyy") + "#group by Medicine_name,Medicine_count,To_Date order by Medicine_count desc ";
                    OleDbConnection connection = new OleDbConnection(connetionString);
                    OleDbDataAdapter dataadapter = new OleDbDataAdapter(sql, connection);
                    ds = new DataSet();
                    connection.Open();
                    dataadapter.Fill(ds);
                    connection.Close();
                    dataGridView1.DataSource = ds;
                    dataGridView1.DataMember = ds.Tables[0].TableName;
                    dataGridView1.Refresh();
}

Answer 1

首先，在您的选择中，您错过了"#And #"

中的空格

另外，假设[To_Date]是一个日期时间字段，问题可能就是如何构建将数据作为字符串传递的select子句。改为使用DateTime字段，当然也总是使用PARAMETRIZED QUERIES。像这样：

string sql = "SELECT Medicine_name,sum(Medicine_count) as Medicine_count,To_Date " +
"FROM Medicine_count_info " +
"WHERE [To_Date] Between @startDate And @endDate " +
"GROUP BY Medicine_name,Medicine_count,To_Date " +
"ORDER BY Medicine_count desc ";
OleDbDataAdapter dataadapter = new OleDbDataAdapter(sql, connection);
dataadapter.SelectCommand.Parameters.AddWithValue("@startDate", startT);
dataadapter.SelectCommand.Parameters.AddWithValue("@startDate", endT);
ds = new DataSet();
dataadapter.Fill(ds);
...