private bool ValidateUser( string userName, string passWord )
{
SqlConnection conn;
SqlCommand cmd;
string lookupPassword = null;

// Check for invalid userName.
// userName must not be null and must be between 1 and 15 characters.
if ( (  null == userName ) || ( 0 == userName.Length ) || ( userName.Length > 15 ) )
{
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Input validation of userName failed." );
return false;
}

// Check for invalid passWord.
// passWord must not be null and must be between 1 and 25 characters.
if ( (  null == passWord ) || ( 0 == passWord.Length ) || ( passWord.Length > 25 ) )
{
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Input validation of passWord failed." );
return false;
}

try
{
// Consult with your SQL Server administrator for an appropriate connection
// string to use to connect to your local SQL Server.
conn = new SqlConnection( "server=localhost;Integrated Security=SSPI;database=pubs" );
conn.Open();

// Create SqlCommand to select pwd field from users table given supplied userName.
cmd = new SqlCommand( "Select pwd from users where uname=@userName", conn );
cmd.Parameters.Add( "@userName", SqlDbType.VarChar, 25 );
cmd.Parameters["@userName"].Value = userName;

// Execute command and fetch pwd field into lookupPassword string.
lookupPassword = (string) cmd.ExecuteScalar();

// Cleanup command and connection objects.
cmd.Dispose();
conn.Dispose();
}
catch ( Exception ex )
{
// Add error handling here for debugging.
// This error message should not be sent back to the caller.
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Exception " + ex.Message );
}

// If no password found, return false.
if ( null == lookupPassword )
{
// You could write failed login attempts here to event log for additional security.
return false;
}

// Compare lookupPassword and input passWord, using a case-sensitive comparison.
return ( 0 == string.Compare( lookupPassword, passWord, false ) );

}