SQLDataReader find value of each row - asp.net

Question

I used to use datasets instead of sqldatareaders and I used to be able to do something like this
If dataset.tables(0).Rows(0)(1).ToString()) = "N" Then
lbl.Text = dataset.tables(0).Rows(0)(2).ToString())
Else
'Do Nothing
End If
This obviously doesn't work with sqldatareaders.
I have code to see if the SQLDatareader has any rows but was wondering if there was a way to get the value of each row
I'm guessing this is possible and i've had a look around but can't seem to find anything
Dim conn As SqlConnection = New SqlConnection("server='h'; user id='w'; password='w'; database='w'; pooling='false'")
conn.Open()
Dim query As New SqlCommand("DECLARE #investor varchar(10), #sql varchar(1000) Select #investor = 69836 select #sql = 'SELECT * FROM OPENQUERY(db,''SELECT * FROM table WHERE investor = ''''' + #investor + ''''''')' EXEC(#sql)", conn)
Dim oDR As SqlDataReader = query.ExecuteReader()
If oDR.HasRows or dataset.tables(0).Rows(0)(1).ToString()) = "N" Then
lbl.Text = dataset.tables(0).Rows(0)(2).ToString())
Else
'Do Nothing
End If
That is the code I have at the moment which obviously doesn't work
Any ideas?
Thanks

Answer 1

When you use the data reader you have to step through each row yourself. Using HasRows is a good start, for it will tell you if the returned result set is empty.
To iterate through the result set you should use the Read() method. It will return true if you are at a row and false when you have moved past the last row.
My Vb is poor so I will give you an example in C# instead:
if (oDR.HasRows && oDR.Read())
{
if (oDR.GetString(0) == "N")
{
lbl.Text = oDr.GetString(1);
}
}
Here I first check that we have a result set with data and then try to move to the first row. If this succeeds I then read the string value of the first column and compare it to "N". If the value is equal to "N" I set the Text property of the lbl variable to the string value of the second column.
This should be equivalent to your algorithm with the dataset. I recommend that you read the MSDN documentation for the SqlDataReader. It is quite good and the example code is useful.