Install .bak file at first run / installation C# By Praveen P.R

//This is to show how to restore your .bak file (SQL Express) when your first  run the application
1. Add this code in your app.config file
add key="ConnectionString" value="Data Source=.\sqlexpress;Initial Catalog=Transactions;Integrated Security=True" 
  add key="ConnectionStringM" value="Data Source=.\sqlexpress;Initial Catalog=master;Integrated Security=True"  
using connectionstring added above
using System.Configuration;this.connectionString = ConfigurationSettings.AppSettings["ConnectionString"]; 
2. Above code is to connect to sql express default database

3.Now when your application runs for the first time check the name of the database if it exists in sql express
with  the above connection string.
4.for eg.
  CheckDBExist("Transactions");//database name
5.

 private bool CheckDBExist(string dbName)
  {
  BLLTransaction bllTransaction = new BLLTransaction(classGlobal.connectionStringM);
  DataSet dsChkDBExist;
  dsChkDBExist = bllTransaction.Select("select * from sys.databases where name = '" + dbName + "'");
  if (dsChkDBExist.Tables[0].Rows.Count == 0)
  {
  DialogResult result = MessageBox.Show("Database not found.\nDo you want to Restore Database?", "Restore Database", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
  if (result == DialogResult.Yes)
  {
  try
  {
  Server mServer = new Server(@".\sqlexpress");
  //mServer.KillAllProcesses("Transactions");
  //mServer.DetachDatabase("Transactions", true);

  //Application.StartupPath.Replace only needed at project devlopment
  File.Move(Application.StartupPath.Replace("bin\\Debug", "") + @"TranDB\Transactions.mdf", @"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions.mdf");
  File.Move(Application.StartupPath.Replace("bin\\Debug", "") + @"TranDB\Transactions_log.ldf", @"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions_log.ldf");

  //File.Move(Application.StartupPath + @"TranDB\Transactions.mdf", @"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions.mdf");
  //File.Move(Application.StartupPath + @"TranDB\Transactions_log.ldf", @"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions_log.ldf");

  StringCollection files = new StringCollection();
 
  files.Add(@"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions.mdf");
  files.Add(@"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\Transactions_log.ldf");

  mServer.AttachDatabase("Transactions", files, AttachOptions.None);
  }
  catch (Exception ex)
  {
  MessageBox.Show(ex.ToString());
  }
  }
  }
  return true;
  }

6.The above code have my bll class which i use for connection above code to give some idea ;)
 7.getSqlExpressPath() //to get sqlexpress path
private string getSqlExpressPath()
{
string path = "";
using (RegistryKey sqlServerKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Microsoft SQL Server"))
{
foreach (string subKeyName in sqlServerKey.GetSubKeyNames())
{
if (subKeyName.StartsWith("MSSQL."))
{
using (RegistryKey instanceKey = sqlServerKey.OpenSubKey(subKeyName))
{
string instanceName = instanceKey.GetValue("").ToString();

if (instanceName == "SQLEXPRESS")//say
{
path = instanceKey.OpenSubKey(@"Setup").GetValue("SQLBinRoot").ToString();
path = Path.Combine(path, "sqlserver.exe");

}
}
}
}
}
return path;
}

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