Invalid attempt to read when no data is present.

Question

3.00/5 (2 votes)

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Hi,
I have an information system which records beach volleyball Players, Teams, Tournaments, Groups, Matches... When I click on select Tournament it redirects to new page - Detail of Tournament, where are shown registrations, groups A,B,C,... And also you can registrate to tour if it is not played Tournament. Session ["Tournament"] is filled with tournament id before it redirects, but it still produce this error, does anyone know why?? Session ["Nickname"] represents logged user.

Error at:

C#

if (Session["Nickname"] == null || DateTime.Now > client.Reader.GetDateTime(1))

throw: Invalid attempt to read when no data is present.

Code:

C#

using Database.Client;
...
protected void Page_Load(object sender, EventArgs e)
    {
        Client client = new Client();
        try
        {
            
            client.Connect();
            client.Command = client.Connection.CreateCommand();
            client.Command.CommandText = "select Name, Tournament_Begining from Tournament where ID = @id";
            client.Command.Parameters.Add("@id", System.Data.SqlDbType.Int, 10, "ID").Value = Session["Tournament"];
            client.Reader = client.Command.ExecuteReader();
            while (client.Reader.Read())
            {
                lblTournamentName.Text = client.Reader.GetString(0);
            }
            if (Session["Nickname"] == null || DateTime.Now > client.Reader.GetDateTime(1))
            {
                Panel3.Visible = false;
            }
            else
            {
                Panel3.Visible = true;
                lblRegister.Visible = false;
            }
            client.Disconnect();
        }
        catch (Exception)
        {
            
            throw;
        }

Thank You for replies!

-Pepin z Hane

Posted 18-Oct-12 12:58pm

Pepin z Hane

Updated 18-Oct-12 13:41pm

v2

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Comments

R. Giskard Reventlov 18-Oct-12 19:22pm

and the error is?

Sergey Alexandrovich Kryukov 18-Oct-12 19:26pm

And..?
--SA

Pepin z Hane 18-Oct-12 19:38pm

Invalid attempt to read when no data is present.

aidin Tajadod 18-Oct-12 20:28pm

It seems you have problem with you client.reader and not session! what is that client.reader? To me it seems each time you call reader, the pointer will go forward! is this a correct assumption? if so, you may want to read once and put it in a variable and use the variable.

[no name] 18-Oct-12 21:11pm

"DateTime.Now > client.Reader.GetDateTime(1)", you have already read everything in the reader and you are trying to read it again.

Pepin z Hane 19-Oct-12 2:57am

Wes Aday You are right. Know I know the solution, thank you!

3 solutions

Solution 2

As I think client.Reader.GetDateTime(1) is NULL. You should check the value before using it. If it is null then it'll show the Exception.
Try this:

C#

if(client.Reader != null){
    if(client.Reader.GetDateTime(1) != null)
    {
        if (Session["Nickname"] == null || DateTime.Now > client.Reader.GetDateTime(1))
        {
            Panel3.Visible = false;
        }
        else
        {
            Panel3.Visible = true;
            lblRegister.Visible = false;
        }
    }
}

--Amit

Posted 18-Oct-12 17:37pm

_Amy

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Abhinav S · Accepted Answer · 2012-10-18T17:30:00

Solution 1

Looks to be a situation where client.Reader is empty or not populated and you are trying to read a value from within it.

Posted 18-Oct-12 17:30pm

Abhinav S

Pepin z Hane · Accepted Answer · 2012-10-18T20:54:00

Oh man, I am reading out of Reader.Read() this is doing the error...

an auxiliary variable should fix it.

C#

Datetime date = new Datetime();
while (client.Reader.Read())
{
    lblTournamentName.Text = client.Reader.GetString(0);
    date = client.Reader.GetDateTime(1);
}
if (Session["Nickname"] == null || DateTime.Now > date)
{
    Panel3.Visible = false;
}

Invalid attempt to read when no data is present.

3 solutions

Solution 1

Solution 2

Solution 3

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