System.Data.SqlClient.SqlException

Question

 Hi guys i'm learning C# now and am trying to create a login application and one of the lines for sql gave me this error

 

System.Data.SqlClient.SqlException: 'An attempt to attach an auto-named database for file C: \*****\**********\Documents\Data.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.'

 

this is the code i was learning:

 

SqlConnection sqlConnection = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C: \*****\**********\Documents\Data.mdf;Integrated Security=True;Connect Timeout=30;");

 

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter("Select Count(*) From Login where Username='" + textBox1.Text + "' and Password = '" + textBox2.Text + "'",sqlConnection);

 

DataTable dataTable = new DataTable();

 

sqlDataAdapter.Fill(dataTable); 

if (dataTable.Rows[0][0].ToString() == "1")

{

this.Hide();

Form2 MainMenu = new Form2();

MainMenu.Show();

}

else

{

MessageBox.Show("Please check your username and password");

}

 

HELP