ASP.Net AJAX Call c# functions - c#

Been looking around for the last few days trying to figure out what the best route is. I am fairly new to ASP.Net so I am in need of a little assistance.
I like the idea of using Master Pages as it will make making changes to the template a lot easier! But I am running into some problems. I will just list them below and see where we can go, maybe this will help some other newbies like myself.
Dynamic Menu:
I am trying to create a menu system that will show certain links depending on the users role. This is simple enough until I just want the link to perform some functions and thats it. So I dont want it to postback or anything. So my next step was to try to use jQuery as I would with my php development. Problem is I cant seem to get my jQUery to call the master page code behind function. I've gone through all the tutorials I could find with WebMethods but just keep getting an error to the like of This type of page is not served.
General Classes:
In PHP sometimes I would have the need to just have some General classes that pertained to a specific area of the application. I would just use these to hold all the function I may need to call from jQuery. Is there something like that in ASP.Net? I tried just adding a class but again couldn't call it from jQuery. Is this something Web Services would be good at? I am still trying to understand their full use. Seems like we could use Web Services as a buffer between the client and the back end classes.
I look forward to any pointers or tips!

Oded and jrummell made it very clear I should probably start with ASP.NET MVC first. It will most likely be an easier road for me moving from php.

Related

Creating javascript function on server side with string.format, best way and alternatives

on one of the project I was delegated to I saw some c# code like this
string.format("some JavaScript function(){{ {0}.setValue and do magic",param1,param2,...");
Then the function was set as index changed method of some JavaScript element.
It's not the first time I saw it but its the first time it struck me so hard. The actual code was enormous and there was large number of parameters passed.
I was wondering if there is a better way (Probably plenty?) cause this seemed for me like a poor one. Writing complex javascript logic can be painful and writing it using string.format is semi insane for me. Can some 1 explain to me what are the alternatives and best practices are?
Thanks for help.
Regards.
If you have not some really need of generating conditional javascript code for the client, bacause that is what the presented code is doing, I would strongly advice to keep JS on client, and deliver it to the client via different standard mechanisms available in browser.
In short
use client side JS delivered via JS files or like a text and after treated like JS, but this is often for advanced scenarious.
use any MVC framework on client side, to avoid continue callback to the server, if you don't really need it, and manage states and appearance of content on your site in easier way.
a) knockout
b) angular.js
... many others...

What is the equivalent approach of ASP.Net's Page Load method in JSP

While working on an ASP.NET project, I really liked the concept of a class for each page or webform, where I could write all the method and actions I want, and more importantly, the Page Load method.
Everyone says that we should avoid using scriplets, either in ASP or JSP.
And I suppose that the Page Load existed for us so that we don't use scriplets anymore.
Because I heard and read many times that we can't know when these scriplets will run, but in the Page Load method, we know exactly how the codes will run and how the page will be rendered.
But in JSP, as far as I know, we don't have this type of server-side class for each page.
Instead we have something called servelts, which everyone encourages to use.
But technically servlets are independent from the normal JSP pages.
So still, I'm using scriplets in my JSP pages, even though I'm trying to make them less as much as I could, but I still use some scriplets to check the Session and some URL parameters.
Isn't there a similar idea or approach to the Page Load (ASP) in JSP?
BalusC was right in saying you are comparing apples to oranges. JSF was created in response to asp.net. (source # 47 minutes) It has grown independently and you might do well to look into all the different frameworks and paradigms out there. While JSF will work similar to asp.net there are plenty of alternatives worth exploring. In .NET you might want to look into MVC4. In Java there is Tapestry, Spring MVC, Seams, etc.
I would start with wiki comparison and go from there. At your stage in the game I would pick one and try to get familiar with it, than try 2 more to do that same thing.
http://en.wikipedia.org/wiki/Comparison_of_web_application_frameworks#Java_2

Capturing/Logging image related data using Django/Python

I come from a ASP.Net background and taking baby steps in open source world. I have an image based application and for every image click I want to log data on server. I'm using Django/Python to host this application.
My understanding is that I need to process this data on client side and send to server using Ajax calls. Please correct me if I'm wrong. In ASP.net world, we had "runat=server" tag for every HTML control that made logging data on server really easy. Is there something similar in Django/Python?
Also, what is the most efficient way of logging image data in this situation?
Thanks in advance. Your help is highly appreciated.
Cheers!!
Your understanding of needing to use AJAX calls is one correct answer.
You could also register onclick JavaScript events for all images and have the JavaScript call a function that submits a form with the needed values for the view to process. That's sort of how ASP.net's PostBack works. The only difference is you're writing the client-side code yourself and nothing is obfuscated with the __VIEWSTATE hidden field.
Basically, ASP.net and Django come from two very different schools of thought. ASP.net's runat=server stuff makes things accessible to the various Page Lifecycle Events (Init, PreLoad, Render, etc) using helpful nuggets from __VIEWSTATE.
Django has no such Page Lifecycle model. It keeps things much simpler: a request is directed to a view method (or class-based view) using urls.py. The view method then returns a response.
There are benefits and drawbacks to both ways of doing things.
The short answer is that different frameworks tend to solve the same problem in different ways.

Extracting data from an ASPX page

I've been entrusted with an idiotic and retarded task by my boss.
The task is: given a web application that returns a table with pagination, do a software that "reads and parses it" since there is nothing like a webservice that provides the raw data. It's like a "spider" or a "crawler" application to steal data that is not meant to be accessed programmatically.
Now the thing: the application is made with standart aspx webform engine, so nothing like standard URLs or posts, but the dreadful postback engine crowded with javascript and non accessible html. The pagination links call the infamous javascript:__doPostBack(param, param) so I think it wouldn't even work if I try even to simulate clicks on those links.
There are also inputs to filter the results and they are also part of the postback mechanism, so I can't simulate a regular post to get the results.
I was forced to do something like this in the past, but it was on a standard-like website with parameters in the querystring like pagesize and pagenumber so I was able to sort it out.
Anyone has a vague idea if this is doable, or if I should tell to my boss to quit asking me to do this retarded stuff?
EDIT: maybe I was a bit unclear about what I have to achieve. I have to parse, extract and convert that data in another format - let's say excel - and not just read it. And this stuff must be automated without user input. I don't think Selenium would cut it.
EDIT: I just blogged about this situation. If anyone is interested can check my post at http://matteomosca.com/archive/2010/09/14/unethical-programming.aspx and comment about that.
Stop disregarding the tools suggested.
No, the parser you can write isn't WatiN or Selenium, both of those Will work in that scenario.
ps. had you mentioned anything on needing to extract the data from flash/flex/silverlight/similar this would be a different answer.
btw, reason to proceed or not is Definitely not technical, but ethical and maybe even lawful. See my comment on the question for my opinion on this.
WatiN will help you navigate the site from the perspective of the UI and grab the HTML for you, and you can find information on .NET DOM parsers here.
Already commented but think thus is actually an answer.
You need a tool which can click client side links and wait while page reloads.
Tool s like selenium can do that.
Also (from comments) WatiN WatiR
#Insane, the CDC's website has this exact problem, and the data is public (and we taxpayers have paid for it), I'm trying to get the survey and question data from http://wwwn.cdc.gov/qbank/Survey.aspx and it's absurdly difficult. Not illegal or unethical, just a terrible implementation that appears to be intentionally making it difficult to get the data (also inaccessible to search engines).
I think Selenium is going to work for us, thanks for the suggestion.

ASP to ASP.NET Helper Functions

I'm looking at converting a web site from classic ASP to ASP.NET. I'm thinking of doing an agile style approach and providing deliverables as quickly as possible and so am thinking of doing a line by line conversion and creating "bad" ASP.NET and have it all in the ASPX file for phase 1 and get that working. That, I figure, will be the fastest and safest (i.e. preserving identical functionality). The next phase would be to split the code out into codebehind and multi-tiers.
I plan on replacing the VBScript in the ASP files with C# in the ASPX files.
So apart from general comments about what I'm planning on doing (which I welcome) the specific question that I have is: Are there any helper functions out there that wrap the VBScript functions from ASP to a C# equivalent that someone's already done?
So I'd be looking for a C# file (library) that has wrappers like:
string Mid(string txt,int start,int length)
{
return txt.SubString(start, length); // or is it start - 1?
}
double Abs(double num)
{
return Math.Abs(num);
}
Look in the Microsoft.VisualBasic namespace to get access to the old VBScript/VB6 functions. You can use them directly from C#.
Additionally, you're in for a shock. ASP.Net uses a different compiler model, and so some of the things you did in Classic ASP aren't allowed at all in ASP.Net. Include files is the big one that comes to mind-- all of your supporting code (code outside of the *.asp file for the page itself) must be re-thought to support the new model.
I don't think a line-by-line approach is a good idea - you'll just end up with a bunch of bad code that you'll still have to refactor. That doesn't sound very Agile to me either.
I'd try breaking the site up logically into modules, and then try rewriting specific pages or modules as ASPX. For example, if the site has an admin section, maybe you could just rewrite the admin portion. Then repeat for the next section. This could be done iteratively for each section until you're done.
I agree with the comment by Jason, and would like to also point out a higher level issue that you'd have to address, if you haven't thought about it already.
Does your classic ASP site make use of session variables to manage state between pages? If so, have you thought about how you're going to share session state between ASP and ASP.NET? Classic ASP and ASP.NET implement session state in different ways, so you will need methods to transfer between the two.
Smaller applications may be easier to "convert", but if you've got a large app that makes heavy use of session variables, you may want to think about other options.
If using ASP.NET MVC is an option for you, I'd take a look at that first. I would think it would be a much easier translation than trying to go from a scripting language to WebForms.
I don't think you gain anything by redoing the site as-is in .Net. Implementing it properly will be so radically different than what you'll start with in .Net that it just seems like wasted effort. Furthermore, it will be very difficult to write unit tests if you implement everything in .aspx pages without even code-behind.
I would aim for an MVC conversion. If you do port it over as-is, at least investigate master pages, that should save you some headaches.

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