Problems connecting to .sdf database through SqlConnection/SqlCeConnection

I'm having immense trouble getting a connection to a .sdf (sql compact edition) database. I can connect initially to extract rows in order to verify a username/password, but when I try to add items to the database, either by a SqlCeConnection/SqlCeCommand command or by trying to add items SqlClient/SqlCommand connection, I have no luck. I get:

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 
all开发者_如何学JAVAow remote connections. (provider: SQL Network Interfaces, error: 26 - Error 
Locating Server/Instance Specified)

when using:

private void button1_Click_1(object sender, EventArgs e)
{
    System.Data.SqlClient.SqlConnection sqlConnection1 =
    new System.Data.SqlClient.SqlConnection("Data Source=C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf");

    System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
    cmd.CommandType = System.Data.CommandType.Text;
    cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
    cmd.Connection = sqlConnection1;

    sqlConnection1.Open();
    cmd.ExecuteNonQuery();
    sqlConnection1.Close();
}

or when I try:

System.Data.SqlClient.SqlConnection sqlConnection1 =
            new System.Data.SqlClient.SqlConnection("Data Source=C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf");

            System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
            cmd.Connection = sqlConnection1;

            sqlConnection1.Open();
            cmd.ExecuteNonQuery();
            sqlConnection1.Close();

Nothing happens, it seems to work until I check the .sdf file and see nothing has been added. I do not have SQL Server CE installed, though I do have 2008 R2 installed (I'm working on someone else's project).

Right now I'm not worried about the security holes, I'm just trying to successfully add a record. Any help would be much appreciated, as I've spent about three or four hours working on something I figure would take about 20 minutes.

Probably you have found the solution by now, but if you use a sdf file, the assembly you should add a reference to System.Data.SqlServerCe and then something like:

SqlCeConnection sqlConnection1= new SqlCeConnection();
sqlConnection1.ConnectionString = "Data Source = C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf";

System.Data.SqlServerCe.SqlCeCommand cmd = System.Data.SqlServerCe.SqlCeCommand;
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
cmd.Connection = sqlConnection1;

sqlConnection1.Open();
cmd.ExecuteNonQuery();
sqlConnection1.Close();

you most to use sqlceconnection and sqlcecommand classes. like this :

        SqlCeConnection conn = new SqlCeConnection(connectionString);            
        SqlCeCommand cmd = conn.CreateCommand();
        conn.Open();