Need help to refactor the nested if else statements

Please find the following code and help me write a better if...else code. I feel this is a very below average way to write else if.

   {
        Retrieve the number in focus.
        string number= getnumber();
        string zipcode;
        int corporate;
        bool bCoverageInBet = false;
        try
        {
            //Get the address and zipcode of the number
            GetAddress(number, out address);

            if (adress!= null)
            {
                zipcode = adress.zipcode
                //if the following are null means this is first time call
                if (!(string.IsNullOrEmpty(_loadedZipcode)) && _address != null)
                {
                    if (zipcode.Equals(_loadedZipcode))
                    {
                        if (adress.Equals(_address ))
                        {
                            if (focusChanged)
                            {
                                return result;
                            }
                        }
                        else
                        {
                            if (bCoverageInBet)
                            {
                                // case 2: Different address and different coverage which is in between, make a call anf get new valus for result                                    
                   开发者_如何转开发             //return the new result
                            }
                            else
                            {
                                return //current result value;
                            }
                        }
                    }   
                }             
                else 
                    {
                        _loadedZipcode = zipcode;
                        _address = adress;
                        GetResponse( out resp)
                        {
                            if ((resp != null))
                            {
                                bool isCorporate = false;
                                corporate = getValues();
                                if (corporate .Equals(100))
                                {
                                   result = true;
                                   return result;
                                }
                                else if (corporate > 0 && corporate < 100)
                                {
                                    //Make a call to get corporate 
                                    bCoverageInBet = true;
                                    LocationResponse objResults;
                                    if (GetAddressbycorporate(out objResults, out errMsg))
                                    {
                                        if (objResults != null)
                                        {
                                            isCorporate = objResults.located;
                                            if (isCorporate )
                                            {
                                                result = true;
                                            }
                                        }

                                    }
                                }
                                return result;
                            }
                            return result;
                        }
                        else
                        {
                            DisplayError("No response ");
                            return result;
                        }
                    }
                }

            else
            {
               //To do: What is address comes null
            }
        }
        catch (System.Exception ex)
        {
            //some ccode
        }
        return result;
   }

Thanks K

Refactor the method into smaller units as appropriate. Also, return early from the method rather than using else clauses.

E.g. instead of

 if (adress!= null)
 {
    zipcode = adress.zipcode

    //if the following are null means this is first time call
    if (!(string.IsNullOrEmpty(_loadedZipcode)) && _address != null)
    {
    }
    else
    {
      return false;
    }
 }
 else
 {
   return false;
 }

Do:

 if (adress == null)
 {
   return false;
 }

 if (string.IsNullOrEmpty(_loadedZipcode) || _address == null)
 {
   return false;
 }

There are quite a few other problems, but that should make the code cleaner to start with.

I don't think anyone is going to "help" you rewrite this code. However, I can offer some suggestions.

I have found it easier to trace my way down to the inner most if and try to rewrite and work my way backwards (up the chain). Depending on the IF block, it is sometimes easier to break them out into separate methods where appropriate.

Also, don't forget about the conditional operator. It can sometimes be clearer to use that than a whole if else block.

For example, property = (boolean expression) ? (true value) : (false value);

Here is a link to MSDN on it: conditonal operator documentation