title: How can I connect to a SDF database? No connection string I try seems to work
body: <p>I've tried literally 50+ different attempts at my connection string for my local database and nothing seems to work. I'm essentially just trying to open a connection the database file so I can dump in the data I've pulled out of my excel spreadsheet. I'm using Visual C# making an offline winform application.</p>
  
  <p>No matter what connection string I try in my app.config, it always fails when it tries to write "dReader" to the database.</p>
  
  <p>The error is usually this depending on what string I try:</p>
  
  <p>"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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)"</p>
  
  <p>I've gone through many online examples and resources and none seem to work. I'm hoping someone here can point out why it's failing.</p>
  
  <p>Here is my app.config in its latest form:</p>
  
  <pre><code>&lt;connectionStrings&gt;
      &lt;add name="DDP_Project.Properties.Settings.DDP_DatabaseConnectionString"
          connectionString="Data Source=E:\Other DDP Projects\DDP_Project_SDF\DDP_Project\DDP_Database.sdf;"
          providerName="Microsoft.SqlServerCe.Client.3.5" /&gt;
  &lt;/connectionStrings&gt;
  </code></pre>
  
  <p></p>
  
  <p>Here is my form code:</p>
  
  <pre><code>    private void Profiles_Click(object sender, EventArgs e)
      {
          profilesDialog.FileName = "[YOUR_UPLOAD_FILE_HERE]";
          var result = profilesDialog.ShowDialog();
  
          if (result == DialogResult.OK)
          {
              HandleFileSelection();
          }
      }
  
      private void HandleFileSelection()
      {
          var file = profilesDialog.FileName;
  
  
           // Create a connection to the file datafile.sdf in the program folder
      string dbfile = new System.IO.FileInfo(System.Reflection.Assembly.GetExecutingAssembly().Location).DirectoryName + "\\DDP_Database.sdf";
      SqlCeConnection connection = new SqlCeConnection("datasource=" + dbfile);
  
  
      string strConnection = ConfigurationManager.ConnectionStrings["DDP_Project.Properties.Settings.DDP_DatabaseConnectionString"].ConnectionString;
  
  
          //Create connection string to Excel work book
          string excelConnectionString = string.Format(
              @"Provider=Microsoft.Jet.OLEDB.4.0;
              Data Source=""{0}"";
              Extended Properties=""Excel 8.0;HDR=YES;""", file
          );
  
          //Create Connection to Excel work book
          OleDbConnection excelConnection = new OleDbConnection(excelConnectionString);
          OleDbCommand cmd = new OleDbCommand("SELECT [ID],[STATUS],[FAN_NUM],[PROFILE_NAME],[DESTINATION_HOST],[USER_ID],[USER_PASSWORD],[PROTOCOL],[PORT],[PATH],[CONTACT_NAME],[CONTACT_EMAIL],[CONTACT_PHONE],[CONTACT_ALT_PHONE],[CONTACT_CITY],[CONTACT_STATE],[CONTACT_CONTACT_TIME] FROM [Sheet1$]", excelConnection);
  
          excelConnection.Open();
          OleDbDataReader dReader;
          dReader = cmd.ExecuteReader();
  
          SqlBulkCopy sqlBulk = new SqlBulkCopy(strConnection);
  
          sqlBulk.DestinationTableName = "Profiles";
          sqlBulk.ColumnMappings.Add("ID", "ID");
          sqlBulk.ColumnMappings.Add("STATUS", "STATUS");
          sqlBulk.ColumnMappings.Add("FAN_NUM", "FAN_NUM");
          sqlBulk.ColumnMappings.Add("PROFILE_NAME", "PROFILE_NAME");
          sqlBulk.ColumnMappings.Add("DESTINATION_HOST", "DESTINATION_HOST");
          sqlBulk.ColumnMappings.Add("USER_ID", "USER_ID");
          sqlBulk.ColumnMappings.Add("USER_PASSWORD", "USER_PASSWORD");
          sqlBulk.ColumnMappings.Add("PROTOCOL", "PROTOCOL");
          sqlBulk.ColumnMappings.Add("PORT", "PORT");
          sqlBulk.ColumnMappings.Add("PATH", "PATH");
          sqlBulk.ColumnMappings.Add("CONTACT_NAME", "CONTACT_NAME");
          sqlBulk.ColumnMappings.Add("CONTACT_EMAIL", "CONTACT_EMAIL");
          sqlBulk.ColumnMappings.Add("CONTACT_PHONE", "CONTACT_PHONE");
          sqlBulk.ColumnMappings.Add("CONTACT_ALT_PHONE", "CONTACT_ALT_PHONE");
          sqlBulk.ColumnMappings.Add("CONTACT_CITY", "CONTACT_CITY");
          sqlBulk.ColumnMappings.Add("CONTACT_STATE", "CONTACT_STATE");
          sqlBulk.ColumnMappings.Add("CONTACT_CONTACT_TIME", "CONTACT_CONTACT_TIME");
  
          sqlBulk.WriteToServer(dReader);
          sqlBulk.Close();
          excelConnection.Close();
  
      }
  
      private void profilesDialog_FileOk(object sender, EventArgs e)
      {
  
  
      }
  }
  </code></pre>
  
  <p>}</p>