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Getting "The underlying provider failed on Open" exception for Sybase database

I am working on application which uses Sybase database and entity framework for accessing database. I am trying to make application to open connection itself and close it. I created model using Sybase database file and now connecting to it to get data. But when I try to get data I get exception "The underlying provider failed to Open".
Here is my code.
var connectionString = metadata=res://*/SampleModel.csdl|res://*/SampleModel.ssdl|res://*/SampleModel.msl; +
provider=iAnywhere.Data.SQLAnywhere; +
provider connection string="DBF=D:\SampleDatabase.db;UID=DBA;PWD=sql"
var dataContext = new SampleContext(connectionString);
var contacts = dataContext.Contacts; --> Here I get this exception.
Note: If I create a DSN in ODBC and use DSN instead of giving filename it gives me Not connected to a database exception. If I open this connection and do not close it, then it works fine. But I don't want to create DSN entry and open it manually. I want my program to do this.

There was problem with my version of Sybase. I was using 3840 build of Sybase 12. I removed it and installed 3769 version and it worked fine. On different forums I found out that latest (3840) is having problems.

How to Connect From WindowsApplication Sqlite Database

I have a Windows Application written in C#, using Sqlite3 as its database. I want to update my database in Host with my Windows Application database.

You can connect to an SQLite3 database using the following code.
SQLiteConnection db = new SQLiteConnection("Data Source=/path/to/file.db;Version=3;");
db.Open();
If you want to specify additional connection parameters, ConnectionStrings.com is always a good resource. Also, you might check out this question which is similar to yours.

connect database with dataGridView

How can I connect my Trgovina.mdf with dataGridView?
I follow this tutorial, but it seems that program doesn't find my database.
Connection string looks like that:
string connString = #"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Klemen\documents\visual studio 2012\Projects\Trgovina\Trgovina\Trgovina.mdf;Integrated Security=True";
Everything else is the same as tutorial example.
Error string is An OLE DB Provider was not specified in the ConnectionString. An example would be, 'Provider=SQLOLEDB;'
Full code looks like this.

The tutorial you talk about in your question use an Access Database and thus uses the OleDB engine to reach and work with the database. Instead your connection string use the syntax reserved for SQLServer LocalDB.
You should change your objects to SqlConnection (instead of OleDbConnection), SqlCommand (instead of OleDbCommand) and so on...
With these changes you should be able to connect to the automatic instance of SqlServer LocalDB. The rest of the tutorial could work or not, depending on what is present in the MDF file used.

You trying to connect to database .mdf file, but you have a wrong provider.
An MDF is a Microsoft SQL Server database not a Jet Database like
Access (*.mdb). You cannot just connect to the flat file and read it.
You would need to mount the database in an instance of SQL Server.
You could install SQL Server 2005 Express
Source
Note: Just download MS SQL Server 2005 Express or later and you must use the System.Data.SqlClient instead of OLE DB to solve your problem.

Connecting to databases in C# : ArgumentException

I'm running Visual Studio Developer Preview 2011 on a Windows 7 x64 machine.
I'm a beginning to learn C# and am having difficulties connecting to a database. I created a database with MS Access and created a connection by using the Connect to a Database option.
Here is the connection string
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\USER\Documents\BlankDB.mdb
I am following this tutorial
I added the variable masterConnectionString to the Project Settings and initialized it with the value of the connection string.
The program compiles but at run-time I get the following error
A first chance exception of type 'System.ArgumentException' occurred in System.Data.dll
Additional information: Keyword not supported: 'provider'. After this the program terminates.
If I remove the provider part from the string the following exception is thrown.
Additional information:
A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible.
Verify that the instance name is correct and that SQL Server is configured to allow remote connections.
(provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
I have been trying for sometime now and this is really frustrating. Is there some other easier method of connecting to databases in C# ? Is it possible to create a SQL Server database from within Visual Studio?
Here is the code that I use to connect to the data base.
static void TryCreateTable()
{
using (SqlConnection con = new SqlConnection(DogsDB.Properties.Settings.Default.BlankDBConnectionString))
{
con.Open();
try
{
using (SqlCommand command = new SqlCommand("CREATE TABLE Dogs1 (Weight INT, Name TEXT, Breed TEXT)", con))
{
command.ExecuteNonQuery();
}
}
catch
{
Console.WriteLine("Table couldn't be created.");
}
}
}

You are following a tutorial for sql server. To connect to your MS Access db, your connection code should look something like this:
OleDbConnection sqlConn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Users\\USER\\Documents\\BlankDB.mdb");
Make sure the backslashes are escaped.
Then you can do
try{
sqlConn.Open();
OleDbCommand command = new OleDbCommand("CREATE....", sqlConn);
command.CommandType = CommandType.Text;
command.ExecuteNonQuery();
}
catch(InvalidOperationException ioe)
{
....
}
catch(OleDbException ode)
{
....
}
sqlConn.Close();

That's an OleDB connection string, not a SQL Server connection string.
You need to use it with an OleDbConnection.
If you want to use SQL Server rather than Access, you can create a database using SQL Server Management Studio or VS's Server Explorer.
You can then connect to it using a SQL Server connection string.
You can see sample connection strings here.

There are several reasons you are getting this error.
1) The reference website is to use SQL Server database not Access.
2) You are running on a x64 operating system which means the following is true.
The Microsoft OLE DB Provider for Jet and the Jet ODBC driver are available in 32-bit versions only. You can't run them in 64 bit mode.
For example, you have a 32-bit application that uses the Microsoft OLE DB Provider for Jet. If you migrate the application to run in the
64-bit mode, the application cannot connect to the data source by
using the Microsoft OLE DB Provider for Jet. This issue occurs because
the application requires a 64-bit version of the Microsoft OLE DB
Provider for Jet. Note also that a website can be either an 32 bit or
64 bit application.
So the solution is use the following:
http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=13255
If you run a program in a 64 bit environment and need to utilize jet
to open an access, excel or text file there are several options to
make this work. •Run the program in WoW64 mode (emulates 32-bit on 64
bit systems). This will make the 32 bit drivers work. •If the
application is an web app hosted on IIS 7 you can choose to configure
the web sites application pool to run in 32-bit mode. •With the new
Office 2010, there will be new drivers coming, "2010 Office System
Driver", which will be provided as booth 32-bit and 64-bit versions.
You can use these drivers to let you application connect to Access,
Excel and text-files in a 64 bit environment, utilizing the new 64 bit
drivers. The provider name is "Microsoft.ACE.OLEDB.14.0". You don't
need to buy or install the Office suite, the components are available
as a separate download.
If you want additiona assistance you will have to provide the code your using.
You should update the code in your question AFTER you have researched and installed the linked library.

Can't connect to Oracle database

I am working on an ASP.NET project, which uses C# for code-behind. It attempts to connect to an Oracle database using the following code, which already existed in the project when I began working on it:
OracleConnection myConnection = new OracleConnection();
myConnection.ConnectionString = ConfigurationManager.ConnectionStrings["OraFinCnString"].ConnectionString;
myConnection.Open();
The application runs locally (opens up in a browser on localhost), and attempts to connect to a remote Oracle Database. When I run it, the The last line above gives the following error:
"InvalidOperationException was unhandled by user code. Attempt to load Oracle client libraries threw BadImageFormatException. This problem will occur when running in 64 bit mode with the 32 bit Oracle client components installed."
The connection string was provided by my client, so I presume it is correct, and this doesn't seem like the sort of error that would be caused by incorrect connection information. But I'm pretty well stumped as to exactly what the problem is, and would appreciate any insight.

Please take a look at the following link. You will need to Install Oracle 11g Oracle Data Access Components
Oracle Provider