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WebService cant access Postgre database

51 New Member
Hi all, could you please help me with my big problem?

I have WebService on IIS. This WebService has methods to control database stored on server.
I am using Postgre database and to access to database I have Npgsql.dll library.
This library is stored in GAC (global assembly cache).

The WebService is not able to open the connection to the database even the connection string is allright, everything seems to be OK. But when the function Open() is called, there occurs an errror "Object reference not set to instance of object" or something like this.

Although, if I access the database with some console application, everything goes well.
Just the bloody WebService :(

Thank you very much for any help.
Zdenek Mach.

ICQ# 173965423
skype: Zdenek_Mach
Mar 21 '07
14 4692
51 New Member
So what?
Do you have some idea?
The exception I got is "The attempted operation was not supported for the type of object referenced".

Mar 28 '07 #11
5,058 Recognized Expert Expert
I think it could be your if statment.
It could be that the _conDatabase object cant be null, or that the parser throws the null exception when your checking it.

So I'd try using a try block
Somewhat like this
Expand|Select|Wrap|Line Numbers
  1. private bool Open()
  2. {
  3.   try{
  4.     _conDatabase.Open();
  5.     return true;
  6.   } 
  7.   catch(Exception) {
  8.     try {
  9.       _conDatabase = new NpgsqlConnection(_sConnectionString);
  10.       _conDatabase.Open();
  11.       return true;
  12.     } 
  13.     catch(Exception) {
  14.       // Fatal error
  15.       return false;
  16.     }
  17.   }
  18. }
This method will also return false on faliure so your app can handle it rather than having your program crash cause of it.
Mar 28 '07 #12
51 New Member
I think it would not help me, but I will try it tomorrow morning.

But didnt mention that my colleague tried it on his PC and it worked well.
Connection was opened...

Thereby I think it could be in some permissions or ASPNET account permissions.
I read lot of about it but I am not able to solve this.

Quite desperate, Zdenek.
Mar 28 '07 #13
51 New Member
Sorry that I am answering too late.
I have found that problem was in my IIS.
It was broken or something, so I have to reinstall OS and than install IIS again.
Now its working well.
Jul 4 '07 #14
45 New Member
I am doing connectivity to PostgreSql from asp.net 2.0 using odbc but i am not able to connect i got error Data source name not found and no default driver specified.

code is written for connectivity is like...

con = new OdbcConnection( "Driver={Postgr eSQL};Server=Ip Address;Port=54 32;Database=dat abase name;Uid=user id;Pwd=;");

from google i found its alternative npgsql but i dont know why,i am not able to download npgsql.dll...tr ue is i am not able to find that dll from internet...

please help me...how i can download dll for npgsql....pleas e provide me source i need it very much....

i am very thankful to u in advance.
Jan 25 '08 #15

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