OleDbDataReader throws error: Missing Parameters

Question

Hi all!

New on his forum. I'm learning C# for about a month now. Met a lot of problems of course, but so far managed to crack 'm all by trying and searching the internet (that's just the way I learn best and how I mastered vba before).

But (hate to admit) now I've stumbled upon an issue I can't seem te solve nor have I been able to find a solution on the internet.

So need some help here.

I have a method retrieving 0 or more records from an Access db which works fine. Retrieved data is moved to datagridview cells.

private void Calendar_PopulatePeriod(DateTime Period)
{
    OleDbCommand cmd = new OleDbCommand("SELECT [PropertyId], [Period], [CalendarText], [StayId] " +
                                        "FROM EVBookings " +
                                        "WHERE [Period] = @PeriodCol " +
                                        "ORDER BY [Period]", conn);
    cmd.Parameters.AddWithValue("@PeriodCol", Period);
    OleDbDataReader rdr = cmd.ExecuteReader();
    int b = 0;
    while (rdr.Read())
    {
ome code....
    }
}

 

Then I have a second method retrieving 1 record which I based on this working method, but which just won't work.

Retrieved data should go to text boxes on a form.

I keep getting this error message: 

An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in System.Data.dll

Additional information: Values for one or more required parameters are missing.

This is the code of the method which is syntactically equal to the first mentioned (working) method:

private void GetStayDetails(double StayId)
{
    OleDbCommand cmd = new OleDbCommand("SELECT [GuestName] , [Date In], [Date Out], [OpenEnded], " +
                                               `[First Month Rent], [Security Deposit], [Monthly Rent], " +
                                                "[First Month Rent To Owner], [Monthly Rent To Owner], " +
                                                "[ES Mgt Fee] " +
                                        "FROM Stays " +
                                        "WHERE StayId = @StayId", conn);
    cmd.Parameters.AddWithValue("@StayId", StayId);
    OleDbDataReader rdr = cmd.ExecuteReader();
    while (rdr.Read())
    {
        Debug.WriteLine("==> " + rdr.GetValue(0));
    }
}

When searching for what's causing the error I tried the following alternative sql commands:

OleDbCommand cmd = new OleDbCommand("SELECT [StayId], [GuestName] FROM Stays", conn);
OleDbCommand cmd = new OleDbCommand("SELECT [StayId], [GuestName] FROM Stays", conn);OleDbCommand cmd = new OleDbCommand("SELECT * FROM Stays WHERE [StayId] = @StayId", conn);
OleDbCommand cmd = new OleDbCommand("SELECT [StayId], [GuestName] FROM Stays WHERE [StayId] = 6500010", conn);

All three work fine.

But this one gives the error again:

OleDbCommand cmd = new OleDbCommand("SELECT [StayId], [GuestName] FROM Stays WHERE [StayId] = @Stayid", conn);

I have not a clue why the sql in one method works fine but not in the other.

Let me know if I need to supply more detail.

 

Cheers!

Tsjallie