为什么我的代码在数据表中填充单元格时停止？

Question

我正在尝试将 accessDatabase 中的特定单元格数据写入数据表。我使用 SELECT 查询获取此数据，但是当将数据写入数据表中的特定单元格时，循环在迭代之前中断甚至一次，当它应该迭代两次时。

这是我正在使用的代码：

DataTable dt = new DataTable();  // Creates Table
dt.Clear();

dt.Columns.Add("Hol/Abs", typeof(string));      // Column 0  
dt.Columns.Add("FirstDay", typeof(DateTime));   // Column 1 
dt.Columns.Add("LastDay", typeof(DateTime));    // Column 2
dt.Columns.Add("TotalDays", typeof(int));       // Column 3
dt.Columns.Add("Reason", typeof(string));       // Column 4

LblName.Text = PassName; //Loads Name

string ConnString = @"Provider = Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\HoliPlanData.accdb;Persist Security Info=False";

string Query = "SELECT PayrollNo FROM [Employee] WHERE (FirstName + ' ' + LastName) = @Name";
string CountQuery = "SELECT COUNT(*) FROM [Holiday]";
        string GetStartQuery = "SELECT StartDate FROM [Holiday] WHERE PayrollNo = @PayrollNo";
        string GetEndQuery = "SELECT EndDate FROM [Holiday] WHERE PayrollNo = @PayrollNo";
        string GetReasonQuery = "SELECT Reason FROM [Holiday] WHERE PayrollNo = @PayrollNo";
        using (OleDbConnection conn = new OleDbConnection(ConnString))
        using (OleDbCommand GetPayroll = new OleDbCommand(Query, conn))            
        {
            conn.Open();                
            GetPayroll.Parameters.Add("@Name", OleDbType.VarChar).Value = LblName.Text;
            int GotPayroll = Convert.ToInt32(GetPayroll.ExecuteScalar());   //Uses Query to Get PayrollNo
            OleDbCommand CountRowsInHol = new OleDbCommand(CountQuery, conn);
            CountRowsInHol.Parameters.AddWithValue("@PayrollNo", OleDbType.Integer).Value = GotPayroll;
            int HolidayCount = (int) (CountRowsInHol.ExecuteScalar()); //Uses CountQuery to Get HowMany lines are in [Holiday] 
            int LoopCount = 0;
            while (LoopCount <= HolidayCount) //Will go though all Lines in [Holiday]
            {                    
                OleDbCommand GetStart = new OleDbCommand(GetStartQuery, conn);
                OleDbCommand GetEnd = new OleDbCommand(GetEndQuery, conn);
                OleDbCommand GetReason = new OleDbCommand(GetReasonQuery, conn);
                GetStart.Parameters.Add("@PayrollNo", OleDbType.Integer).Value = GotPayroll;

                GetEnd.Parameters.Add("@PayrollNo", OleDbType.Integer).Value = GotPayroll;
                GetReason.Parameters.Add("@PayrollNo", OleDbType.Integer).Value = GotPayroll;
                DateTime StartHold = Convert.ToDateTime(GetStart.ExecuteScalar());
                DateTime EndHold = Convert.ToDateTime(GetEnd.ExecuteScalar());
                string ReasonHold = (GetReason.ExecuteScalar()).ToString();
                dt.Rows[LoopCount]["FirstDay"] = StartHold;
                dt.Rows[LoopCount]["LastDay"] = EndHold;
                dt.Rows[LoopCount]["Reason"] = ReasonHold;
                LoopCount = LoopCount + 1;
            }
        }

我知道它很长，但它很基础。代码中断于 ..

dt.Rows[LoopCount]["FirstDay"] = StartHold;

..而不是写入数据表。任何帮助或建议将不胜感激，而且我非常愿意接受关于更好地格式化我的代码的明确建议，以便它更容易阅读和更普遍标准。

Answer 1

不完全确定，但替换为：

会不会是个小错误

dt.Rows[LoopCount]["FirstDay"] = StartHold;

与：

dt.Rows[LoopCount].["FirstDay"] = StartHold;

也许我错了，但只想知道 dt.Rows[0] 是否包含字段 ["FirstDay"].

Answer 2

感谢您的帮助，CrowCoder 为我指明了正确的方向。我从不添加行！使用这段代码，一切都很好，所以希望其他新手编码员不会像我一样被卡住！

从 dt.rows[LoopCount] 替换为以下

DataRow NewLine = dt.NewRow();
NewLine["Hol/Abs"] = "Holiday";
NewLine["FirstDay"] = StartHold;
NewLine["LastDay"] = EndHold;
NewLine["TotalDays"] = (EndHold - StartHold);
NewLine["Reason"] = ReasonHold;
dt.Rows.Add(NewLine);

为什么我的代码在数据表中填充单元格时停止？

Why does my code stop when populating cells in a datatable?

c#

database

datatable

oledbconnection

oledbcommand