you have first close your first reader then only you can use the second one ......
The reason behind this is,only one
datareader
per connection can be active at the same time.
So, you will have to create not only another reader but also another
connection to use two of them at the same time.
Instead of that what you are doing you can use
DataSet
and Retrieve both table into it....
And then simply compare both table values like,
ds.Table[0].rows[0]["Column_name"] == ds.Table[1].rows[0]["Column_name"]
I hope this will help you.