Asp. NET Hash encrypted password

asp.net| encryption private void Loginbutton_click (Object Sender,system.eventargs e)
{
String sql=string.format ("Select password from Administrator where adminid= ' {0} ', useridbox.text);"
SqlConnection conn=new SqlConnection (configurationsettings.appsettings["connectionString"));
SqlDataReader myreader=new SqlCommand (sql,conn). ExecuteReader ();
if (myreader. Read ())
{
String Hashed=formsauthentication.hashpasswordforstoringinconfigfile (Passwordtextbox.text, "SHA1");
Hash the password entered by the user and compare it to the hash value of the database
if (hash==myreader["password"]). ToString ())
{
FormsAuthentication.RedirectFromLoginPage (useridbox.text,true);/Go to request page
}
Else
result.text= "Password Error";
}
Else
result.text= "User does not exist";
Conn. Close ();
}