the type initializer for Oracle.DataAccess.Client.OracleConnection threw an exception

[Arjun_Sarankulu]

I have created a application which connection to sql server database as well as oracle database
The application is working fine at my end
And to connect to oracle i used following namespace
using Oracle.DataAccess;
using Oracle.DataAccess.Client;
But when i run the application on user end
It gives following exception
the type initializer for Oracle.DataAccess.Client.OracleConnection threw an exception
And I am giving only exe, config file

[nmaillet]

Are the Oracle assemblies installed on the client's machine?

[Arjun_Sarankulu]

I have developed the application on remote desktop there its working fine
How to install Oracle assemblies on client machine

[sknake]

Type initializers can fail for a number of reasons. The exception being thrown should have an InnerException with more detail as to why initialization failed.

[rohitosu]

Hello,

This error is occuring because of assembly type mismatch. Try updating the assembly version which you have when/where your program is working fine.

[AndrewGrinder]

Ok, when you know for sure other applications that used the same process worked... on your new application make sure you have the reference and the three dll files...

I downloaded ODAC1120320Xcopy_32bit this from the Oracle site:

http://www.oracle.com/technetwork/database/windows/downloads/utilsoft-087491.html

Reference: Oracle.DataAccess (ODAC1120320Xcopy_32bit\odp.net4\odp.net\bin\4\Oracle.DataAccess.dll)

3 Files

oci.dll (ODAC1120320Xcopy_32bit\instantclient_11_2\oci.dll)

oraociei11.dll (ODAC1120320Xcopy_32bit\instantclient_11_2\oraociei11.dll)

OraOps11w.dll (ODAC1120320Xcopy_32bit\odp.net4\bin\OraOps11w.dll)

When I tried to create another application with the correct reference and files I would receive that error message.

The fix: Highlighted all three of the files and selected "Copy To Output" = Copy if newer. I did copy if newer since one of the dll's is above 100MB and any updates I do will not copy those files again.

I also ran into a registry error, this fixed it.

public void checkRegistryForOracleNLS()
{
    RegistryKey oracle = Registry.LocalMachine.CreateSubKey(@"SOFTWARE\ORACLE");
    oracle.SetValue("NLS_LANG", "AMERICAN_AMERICA.WE8MSWIN1252");
}

After that everything worked smooth, I hope it helps.