如何将asp.net c#中的日期与sql进行比较 我的时间表表中有两列 开始日期（格式为DD-MM-YYYY） 结束日期

如果我从登录页面登录，我想检查当前日期是否在

开始日期

和

结束日期

之间；如果是，我可以登录

如何在C#…asp.net中进行比较

我已成功在登录页面中打印当前日期

lblMsg.Text= DateTime.Now.ToString("dd-MM-yyyy");  

我正在使用asp.net和c#

用于以DD/MM/YYYY格式存储日期的代码 CultureInfo provider=CultureInfo.InvariantCulture

        DateTime startdate = DateTime.ParseExact(tbstartdate.Text.ToString().Trim(), "dd/MM/yyyy", provider);
        DateTime enddate = DateTime.ParseExact(tbenddate.Text.ToString().Trim(),"dd/MM/yyyy",provider);
        string sql = "INSERT INTO TimeTable(start_date,end_date)"
     + "VALUES (@startdate,@enddate)";
        SqlConnection conn = new SqlConnection(ConnectionString);
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql, conn);

        cmd.Parameters.Add("@startdate", SqlDbType.DateTime).Value = startdate;
        cmd.Parameters.Add("@enddate", SqlDbType.DateTime).Value = enddate;

        cmd.Prepare();
        n = cmd.ExecuteNonQuery();

        conn.Close();

        DateTime date = DateTime.ParseExact(DateTime.Now.ToString("dd/mm/yyyy"), "dd/MM/yyyy", provider);
      //  DateTime date=DateTime.Now.ToString("dd/mm/yyyy");

        string query1 = "select * from TimeTable where ((start_date >= @date1 and End_date<= @date2) and UserType=@type)";
        SqlConnection conn = new SqlConnection(ConnectionString);
        conn.Open();
        SqlCommand com = new SqlCommand(query1, conn);
        com.Parameters.Add("@type",dpusertype.SelectedItem.Text.ToString());
        com.Parameters.Add("@date1",date);
        com.Parameters.Add("@date2", date);
        com.CommandType = CommandType.Text;
        SqlDataAdapter da = new SqlDataAdapter(com);
        DataTable dt = new DataTable();
        da.Fill(dt);

用于在登录页面上检查日期的代码 CultureInfo provider=CultureInfo.InvariantCulture

        DateTime startdate = DateTime.ParseExact(tbstartdate.Text.ToString().Trim(), "dd/MM/yyyy", provider);
        DateTime enddate = DateTime.ParseExact(tbenddate.Text.ToString().Trim(),"dd/MM/yyyy",provider);
        string sql = "INSERT INTO TimeTable(start_date,end_date)"
     + "VALUES (@startdate,@enddate)";
        SqlConnection conn = new SqlConnection(ConnectionString);
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql, conn);

        cmd.Parameters.Add("@startdate", SqlDbType.DateTime).Value = startdate;
        cmd.Parameters.Add("@enddate", SqlDbType.DateTime).Value = enddate;

        cmd.Prepare();
        n = cmd.ExecuteNonQuery();

        conn.Close();

        DateTime date = DateTime.ParseExact(DateTime.Now.ToString("dd/mm/yyyy"), "dd/MM/yyyy", provider);
      //  DateTime date=DateTime.Now.ToString("dd/mm/yyyy");

        string query1 = "select * from TimeTable where ((start_date >= @date1 and End_date<= @date2) and UserType=@type)";
        SqlConnection conn = new SqlConnection(ConnectionString);
        conn.Open();
        SqlCommand com = new SqlCommand(query1, conn);
        com.Parameters.Add("@type",dpusertype.SelectedItem.Text.ToString());
        com.Parameters.Add("@date1",date);
        com.Parameters.Add("@date2", date);
        com.CommandType = CommandType.Text;
        SqlDataAdapter da = new SqlDataAdapter(com);
        DataTable dt = new DataTable();
        da.Fill(dt);

获取错误 calendar System.Globalization.GregorianCalendar中不支持由字符串表示的日期时间。 描述`

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要同步以下类型：

将c#日期转换为sql格式

var sqlFormattedDate = myDateTime.Date.ToString("yyyy-MM-dd HH:mm:ss");