Insert to Database.sdf file

string strConnection = ConfigurationManager.ConnectionStrings["Database1Entities"].ConnectionString;
           using (var conn = new SqlCeConnection(string.Format("Data Source=Database1.sdf;", strConnection)))
           {
               conn.Open();

               try
               {
                   SqlCeCommand dbCmd = new SqlCeCommand();

String sqlAddNew = "INSERT INTO tbl_Credantials (password,username ) Values(@password,@username)";
               dbCmd = new SqlCeCommand(sqlAddNew, conn);


dbCmd.Parameters.Add("@password", SqlDbType.NVarChar).Value = txtuserID.Text;
dbCmd.Parameters.Add("@username", SqlDbType.NVarChar).Value = txtUsername.Text;

                   dbCmd.ExecuteNonQuery();
                                 }
               catch (SqlCeException)
               {
                   throw;
               }
               finally
               {
                   if (conn.State == ConnectionState.Open) conn.Close();
               }
           }

<configuration>
  <connectionStrings>
    <add name="Database1Entities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlServerCe.3.5;provider connection string=&quot;Data Source=|DataDirectory|\Database1.sdf&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>