Question

你能帮助我吗，我有一个按钮来过滤数据，日期范围基于我的2 datetimepicker（datefrom和dateto），下面是我的代码，当我点击按钮时它什么也没显示。你能帮我解决一下这个问题吗？我是C＃中的新人。

MySqlConnection mcon = new MySqlConnection("datasource=localhost;port=3306;username=8888;password=888888");
MySqlDataAdapter mda = new MySqlDataAdapter("select * from bio_db.daily_data2 where Date between '" + datefrom.Value.ToString() + "' and '" + dateto.Value.ToString() + "' ", mcon);
mcon.Open();
DataSet ds = new DataSet();
mda.Fill(ds);
dbgrid1.DataSource = ds;
dbgrid1.Refresh();
mcon.Close();

Answer 1

您需要将dateFrom和dateTo值转换为DateTime

DateTime dtFrom =Convert.ToDateTime(DatePicker1.Text); //some DateTime value, e.g. DatePicker1.Text;
DateTime dtTo =Convert.ToDateTime(DatePicker2.Text); //some DateTime value, e.g. DatePicker1.Text;
MySqlConnection mcon = new MySqlConnection("datasource=localhost;port=3306;username=8888;password=888888");
MySqlDataAdapter mda = new MySqlDataAdapter("select * from bio_db.daily_data2 where Date between '" + dtFrom.ToString("MM/dd/yyyy")+ "' and '" + dtTo.ToString("MM/dd/yyyy") + "' ", mcon);
DataSet ds = new DataSet();
mda.Fill(ds);
dbgrid1.DataSource = ds;
dbgrid1.Refresh();
mcon.Close();

Answer 2

缺少此行：

MySqlCommandBuilder mcb = new MySqlCommandBuilder(mda);

来源：

https://dev.mysql.com/doc/connector-net/en/connector-net-tutorials-data-adapter.html http://www.techonthenet.com/mysql/between.php

所以代码应该是：

MySqlConnection mcon = new MySqlConnection("datasource=localhost;port=3306;username=8888;password=888888");
string query = string.Format("select * from bio_db.daily_data2 where Date "
                           + "BETWEEN CAST('{0}' AS DATE) AND CAST('{1}' AS DATE) ", 
                             dateFrom.Value.ToString("M/d/yyyy"), 
                             dateTo.Value.ToString("M/d/yyyy"));
MySqlDataAdapter mda = new MySqlDataAdapter(query, mcon);
MySqlCommandBuilder mcb = new MySqlCommandBuilder(mda); //added code
mcon.Open();
DataTable dt = new DataTable();
mda.Fill(dt);
dbgrid1.DataSource = dt;
dbgrid1.Refresh();
mcon.Close();

Answer 3

您的数据库的date值为date type，并且您将string与date进行比较，但不匹配。

您需要convert start和end日期为date

select * from bio_db.daily_data2 where Date between STR_TO_DATE('" + datefrom.Value.ToString() + "','%m/%d/%Y') and STR_TO_DATE('" + dateto.Value.ToString() + "','%m/%d/%Y') "

您需要指定存储在数据库中的确切格式来代替'%m/%d/%Y'。

使用参数化Sql

您当前的代码向Sql injection开放，最好使用parameterized sql。请勿将值add parameters连接到查询。

Answer 4

我认为你需要将datefrom和dateto值转换为Database Date格式并输入

Answer 5

大家好我已经找到了缺失的链接。这是更正后的脚本。谢谢大家！

DateTime dtFrom = Convert.ToDateTime(datefrom.Text); //some DateTime value, e.g. DatePicker1.Text;
DateTime dtTo = Convert.ToDateTime(dateto.Text); //some DateTime value, e.g. 
DatePicker1.Text;<n>MySqlConnection mcon = new MySqlConnection("datasource=localhost;port=3306;username=8888;password=8888888");
MySqlDataAdapter mda = new MySqlDataAdapter("select * from bio_db.daily_data2 where Date between '" + dtFrom.ToString("yyyy/MM/dd") + "' and '" + dtTo.ToString("yyyy/MM/dd") + "' ", mcon);

        System.Data.DataSet ds = new System.Data.DataSet();
        mcon.Open();
        mda.Fill(ds, "root");
        dbgrid1.DataSource = ds.Tables["root"];
        dbgrid1.Refresh();
        mcon.Close();

如何使用datetimepicker通过数据库过滤日期

5 个答案: