C# 带有数据源的asp日历在表中不存在的日期上没有差异

因此，基本上它是一个asp日历，显示员工申请的休假次数，每次有人申请休假时，槽号都会下降。这一切都很好，但我正试图从数据库中设置可用的插槽。因此，我在table setshrinkage上有一个数据列，它获取为某些日期设置的人员编制，并尝试从批准的带有人员编制的表中减去特定日期的人数。编制表如下所示

例如，在2018年8月27日的日历中，我想从批准的表格中减去9减去2018年8月27日的计数。但是当我尝试这个方法时，我得到了一个错误的对象引用，没有设置为对象的实例。我理解这是因为剩余日期的数据为空。那我怎么才能让它工作呢？提前谢谢

class Sample
{
    public DateTime Date { get; set; }
    public int SlotAvailable { get; set; }
    public int Pending { get; set; }
    public int HeadCount { get; set; }
} 

List<Sample> samples = new List<Sample>();

protected void FillLeaveplannerDataset()
{
    cal2.VisibleDate = cal2.TodaysDate;
    DateTime firstDate = new DateTime(cal2.VisibleDate.Year, cal2.VisibleDate.Month, 1).AddDays(-6);
    DateTime lastDate = new DateTime(cal2.VisibleDate.Date.AddMonths(1).Year, cal2.VisibleDate.Date.AddMonths(1).Month, 1).AddDays(7);
    dsleaveplanner = GetCurrentMonthData(firstDate, lastDate);
}

protected DateTime GetFirstDayOfNextMonth()
{
    int monthNumber, yearNumber;
    if (cal2.VisibleDate.Month == 12)
    {
        monthNumber = 1;
        yearNumber = cal2.VisibleDate.Year + 1;
    }
    else
    {
        monthNumber = cal2.VisibleDate.Month + 1;
        yearNumber = cal2.VisibleDate.Year;
    }
    DateTime lastDate = new DateTime(yearNumber, monthNumber, 1);
    return lastDate;
}

protected DataSet GetCurrentMonthData(DateTime firstDate, DateTime lastDate)
{
    DataSet dsMonth = new DataSet();
    MySqlConnection con = new MySqlConnection("Server=localhost;Database=mydb;Uid=myid;Pwd=abc123;");
    string caldate = "Select * From approved Where date >= @firstDate And date <= @lastDate And site=@site And skill=@skill And shift=@shift Group By date";
    MySqlCommand cmd = new MySqlCommand(caldate, con);
    cmd.Parameters.AddWithValue("@firstDate", firstDate);
    cmd.Parameters.AddWithValue("@lastDate", lastDate);
    cmd.Parameters.AddWithValue("@site", lblsite.Text);
    cmd.Parameters.AddWithValue("@skill", lblskill.Text);
    cmd.Parameters.AddWithValue("@shift", lblshift.Text);
    MySqlDataAdapter mysqlDataAdapter = new MySqlDataAdapter(cmd);

    try
    {
         mysqlDataAdapter.Fill(dsMonth);
    }
    catch { }

    return dsMonth;
}

protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
{
    foreach (DataRow dr in dsleaveplanner.Tables[0].Rows)
    {
        nextDate = (DateTime)dr["date"];
        MySqlConnection conn = new MySqlConnection("Server=localhost;Database=mydb;Uid=myid;Pwd=abc123;");
        string hc = "SELECT headCount FROM setshrinkage WHERE date = @date";
        MySqlCommand cmd1 = new MySqlCommand(hc, conn);
        cmd1.Parameters.AddWithValue("@date", nextDate);
        conn.Open();
        string hcount = cmd1.ExecuteReader().ToString();
        Int32 hcount1 = Convert.ToInt32(hcount);
        conn.Close();
        string cntdate = "SELECT COUNT(date) FROM approved WHERE date = @date";
        string cntdate2 = "SELECT COUNT(date) FROM pending WHERE date = @date";
        MySqlCommand cmd2 = new MySqlCommand(cntdate, conn);
        MySqlCommand cmd3 = new MySqlCommand(cntdate2, conn);
        cmd2.Parameters.AddWithValue("@date", nextDate);
        cmd3.Parameters.AddWithValue("@date", nextDate);
        conn.Open();
        string count = cmd2.ExecuteScalar().ToString();
        string count2 = cmd3.ExecuteScalar().ToString();
        var slot2 = Convert.ToInt32(count);
        Int32 slot3 = hcount1 - slot2;
        string slot4 = slot3.ToString();
        conn.Close();

        samples.Add(new Sample { Date = nextDate, SlotAvailable = slot4, Pending = count2, HeadCount = hcount1 });
    }
    
    if (samples.Any(x => x.Date == e.Day.Date))
    {
        e.Cell.BackColor = System.Drawing.Color.Orange;
        Environment.NewLine.ToString();
        e.Cell.ForeColor = System.Drawing.Color.Red;
        e.Cell.Font.Size = 9;
        e.Cell.Controls.Add(new LiteralControl("<p></p>Slot available:"));
        e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().SlotAvailable.ToString()));
        e.Cell.Controls.Add(new LiteralControl("<p></p>Pending:"));
        e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().Pending.ToString()));
    }
    else
    {
        e.Cell.Font.Size = 9;
        e.Cell.Controls.Add(new LiteralControl("<p>Slot available: </p>"));
        e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().HeadCount.ToString()));
        e.Cell.Controls.Add(new LiteralControl("<p></p>Pending: 0"));
    }
}

我已经找到了一种用下面的代码修复错误的方法

    protected DataSet GetCurrentMonthData(DateTime firstDate, DateTime lastDate)
    {
        DataSet dsMonth = new DataSet();
        MySqlConnection con = new MySqlConnection("Server=localhost;Database=mydb;Uid=myid;Pwd=abc123;");
        string caldate = "Select * From setshrinkage Where date >= @firstDate And date <= @lastDate Group By date";
        MySqlCommand cmd = new MySqlCommand(caldate, con);
        
        cmd.Parameters.AddWithValue("@firstDate", firstDate);
        cmd.Parameters.AddWithValue("@lastDate", lastDate);
        MySqlDataAdapter mysqlDataAdapter = new MySqlDataAdapter(cmd);
        try
        {
            mysqlDataAdapter.Fill(dsMonth);
        }
        catch { }
        return dsMonth;
    }

protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
{

    DateTime nextDate;
    if (dsleaveplanner != null)
    {
        
            foreach (DataRow dr in dsleaveplanner.Tables[0].Rows)
            {
                nextDate = (DateTime)dr["date"];
                var hcount = (dr["headCount"].ToString());
                Int32 hcount1 = Convert.ToInt32(hcount);
                
                MySqlConnection conn = new MySqlConnection("Server=localhost;Database=mydb;Uid=myid;Pwd=abc123;");
                string cntdate = "SELECT COUNT(date) FROM approved WHERE date = @date";
                string cntdate2 = "SELECT COUNT(date) FROM pending WHERE date = @date";
                MySqlCommand cmd2 = new MySqlCommand(cntdate, conn);
                MySqlCommand cmd3 = new MySqlCommand(cntdate2, conn);
                cmd2.Parameters.AddWithValue("@date", nextDate);
                cmd3.Parameters.AddWithValue("@date", nextDate);
                conn.Open();
                string count = cmd2.ExecuteScalar().ToString();
                string count2 = cmd3.ExecuteScalar().ToString();
                var slot2 = Convert.ToInt32(count);
                Int32 slot3 = hcount1 - slot2;
                string slot1 = Convert.ToString(slot3);
                string slot4 = slot3.ToString();
                conn.Close();

                samples.Add(new Sample { Date = nextDate, SlotAvailable = slot1, Pending = count2 });
                if (samples.Any(x => x.Date == e.Day.Date))
                {
                    Environment.NewLine.ToString();
                    e.Cell.Font.Size = 11;
                    e.Cell.Controls.Add(new LiteralControl("<p></p>Slot available:"));
                    e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().SlotAvailable.ToString()));
                    e.Cell.Controls.Add(new LiteralControl("<p></p>Pending:"));
                    e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().Pending.ToString()));

                }
                else
                {
                    e.Cell.ForeColor = System.Drawing.Color.Red;
                    e.Cell.Font.Size = 9;
                    e.Cell.Controls.Add(new LiteralControl("<p></p>Slot available:"));
                    e.Cell.Controls.Add(new LiteralControl(slot1));
                    e.Cell.Controls.Add(new LiteralControl("<p></p>Pending:0"));
                }
            }
    }

但我发现了一个完全不同的问题，如下图所示

---

标签会重复显示，如上所示。有人能帮我修复它吗？

它是通过将条件排除在循环之外来修复的。日历看起来很整洁。谢谢你的支持

protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
{

DateTime nextDate;
if (dsleaveplanner != null)
{

        foreach (DataRow dr in dsleaveplanner.Tables[0].Rows)
        {
            nextDate = (DateTime)dr["date"];
            var hcount = (dr["headCount"].ToString());
            Int32 hcount1 = Convert.ToInt32(hcount);

            MySqlConnection conn = new MySqlConnection("Server=localhost;Database=mydb;Uid=myid;Pwd=abc123;");
            string cntdate = "SELECT COUNT(date) FROM approved WHERE date = @date";
            string cntdate2 = "SELECT COUNT(date) FROM pending WHERE date = @date";
            MySqlCommand cmd2 = new MySqlCommand(cntdate, conn);
            MySqlCommand cmd3 = new MySqlCommand(cntdate2, conn);
            cmd2.Parameters.AddWithValue("@date", nextDate);
            cmd3.Parameters.AddWithValue("@date", nextDate);
            conn.Open();
            string count = cmd2.ExecuteScalar().ToString();
            string count2 = cmd3.ExecuteScalar().ToString();
            var slot2 = Convert.ToInt32(count);
            Int32 slot3 = hcount1 - slot2;
            string slot1 = Convert.ToString(slot3);
            string slot4 = slot3.ToString();
            conn.Close();

            samples.Add(new Sample { Date = nextDate, SlotAvailable = slot1, Pending = count2 });

        }
        if (samples.Any(x => x.Date == e.Day.Date))
            {
                Environment.NewLine.ToString();
                e.Cell.Font.Size = 11;
                e.Cell.Controls.Add(new LiteralControl("<p></p>Slot available:"));
                e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().SlotAvailable.ToString()));
                e.Cell.Controls.Add(new LiteralControl("<p></p>Pending:"));
                e.Cell.Controls.Add(new LiteralControl(samples.Where(x => x.Date == e.Day.Date).FirstOrDefault().Pending.ToString()));

            }
            else
            {
                e.Cell.ForeColor = System.Drawing.Color.Red;
                e.Cell.Font.Size = 9;
                e.Cell.Controls.Add(new LiteralControl("<p></p>Slot available:"));
                e.Cell.Controls.Add(new LiteralControl(slot1));
                e.Cell.Controls.Add(new LiteralControl("<p></p>Pending:0"));
            }
}

---

哦，尝试在此处应用ExecuteScalar而不是ExecuteReader字符串hcount=cmd1.ExecuteReader.ToString；还可以使用断点在此处设置字符串计数=cmd2.ExecuteScalar.ToString；字符串count2=cmd3.ExecuteScalar.ToString；并检查是否收到任何值？好的，我会尝试now@ershoaib我在第行遇到了相同的错误：string hcount=cmd1.ExecuteScalar.ToString；对象引用未设置为对象的实例。请在采样后关闭foreach循环。Addnew Sample{Date=nextDate，SlotAvailable=slot1，Pending=count2}；这条线