database still exists after deletion

hi

Basically, I create a database with sql, then I delete it manually(not via sql statment. This is a problem which I realise. In fact, you can't delete the database because the VS 2005 still is using it) I run the same code again,
then it says the database still exists, even it is physically destroied.

--Here is the errors:
System.Data.SqlClient.SqlException: Database 'riskDatabase' already exists.
at System.Data.SqlClient.SqlConnection.OnError(SqlExc eption exception, Boolea
n breakConnection)

--The evidence that the database doesn't exist physically:
Unhandled Exception: System.Data.SqlClient.SqlException: Cannot open database "riskDatabase" requested by the login. The login failed.

--The code:
/*
* C# code to programmically create
* database and table. It also inserts
* data into the table.
*/

using System;
using System.Collections.Generic;
using System.Text;

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.IO;

namespace riskWizard
{
public class RiskWizard
{
// Sql
private string connectionString;
private SqlConnection connection;
private SqlCommand command;

// Database
private string databaseName;
private string currDatabasePath;
private string database_mdf;
private string database_ldf;

public RiskWizard(string databaseName, string currDatabasePath, string database_mdf, string database_ldf)
{
this.databaseName = databaseName;
this.currDatabasePath = currDatabasePath;
this.database_mdf = database_mdf;
this.database_ldf = database_ldf;
}

private void executeSql(string sql)
{
// Create a connection
connection = new SqlConnection(connectionString);

// Open the connection.
if (connection.State == ConnectionState.Open)
connection.Close();

connection.ConnectionString = connectionString;
connection.Open();

command = new SqlCommand(sql, connection);
try
{
command.ExecuteNonQuery();
}
catch (SqlException e)
{
Console.WriteLine(e.ToString());
}
}

public void createDatabase()
{
string database_data = databaseName + "_data";
string database_log = databaseName + "_log";

connectionString
= "Data Source=.\\SQLExpress;Initial Catalog=;Integrated Security=SSPI;";

string sql = "CREATE DATABASE " + databaseName + " ON PRIMARY"
+ "(name=" + database_data + ",filename=" + database_mdf + ",size=3,"
+ "maxsize=5,filegrowth=10%)log on"
+ "(name=" + database_log + ",filename=" + database_ldf + ",size=3,"
+ "maxsize=20,filegrowth=1)";

executeSql(sql);
}

public void dropDatabase()
{
connectionString
= "Data Source=.\\SQLExpress;Initial Catalog=" + databaseName + ";Integrated Security=SSPI;";

string sql = "DROP DATABASE " + databaseName;

executeSql(sql);
}

// Create table.
public void createTable(string tableName)
{
connectionString
= "Data Source=.\\SQLExpress;Initial Catalog=" + databaseName + ";Integrated Security=SSPI;";

string sql = "CREATE TABLE " + tableName +
"(userId INTEGER IDENTITY(1, 1) CONSTRAINT PK_userID PRIMARY KEY," +
"name CHAR(50) NOT NULL, address CHAR(255) NOT NULL, employmentTitle TEXT NOT NULL)";

executeSql(sql);
}

// Insert data
public void insertData(string tableName)
{
string sql;

connectionString
= "Data Source=.\\SQLExpress;Initial Catalog=" + databaseName + ";Integrated Security=SSPI;";

sql = "INSERT INTO " + tableName + "(userId, name, address, employmentTitle) " +
"VALUES (1001, 'Puneet Nehra', 'A 449 Sect 19, DELHI', 'project manager') ";
executeSql(sql);

sql = "INSERT INTO " + tableName + "(userId, name, address, employmentTitle) " +
"VALUES (1002, 'Anoop Singh', 'Lodi Road, DELHI', 'software admin') ";
executeSql(sql);

sql = "INSERT INTO " + tableName + "(userId, name, address, employmentTitle) " +
"VALUES (1003, 'Rakesh M', 'Nag Chowk, Jabalpur M.P.', 'tester') ";
executeSql(sql);

sql = "INSERT INTO " + tableName + "(userId, name, address, employmentTitle) " +
"VALUES (1004, 'Madan Kesh', '4th Street, Lane 3, DELHI', 'quality insurance mamager') ";
executeSql(sql);
}

public static void Main(String[] argv)
{
string databaseName = "riskDatabase";
string currDatabasePath = "E:\\liveProgrammes\\cSharpWorkplace\\riskWizard\\A pp_Data";
// Need to be more flexible.
string database_mdf = "'E:\\liveProgrammes\\cSharpWorkplace\\riskWizard\\ App_Data\\riskDatabase.mdf'";
string database_ldf = "'E:\\liveProgrammes\\cSharpWorkplace\\riskWizard\\ App_Data\\riskDatabase.ldf'";

RiskWizard riskWizard = new RiskWizard(databaseName, currDatabasePath, database_mdf, database_ldf);
riskWizard.createDatabase();
riskWizard.createTable("userTable");
riskWizard.insertData("userTable");
//riskWizard.dropDatabase();
}
}
}Have someone tried to create a database then drop it in runtime?