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How to achieve a dynamic RegularExpressionValidator via the constructor?

I'm building a Custom Control which simply inherits from RegularExpressionValidator. In the constructor I need to be able to see what the viewstate value of the control is so that I can use that value during the construction to determine which validation expression I need it to use.
The problem is the constructor does not have access to viewstate when it is called. At least viewstate is always null due to the timing when the constructor is called.
I have tried overriding the render method, but for some reason, even though the control has access to the viewstate the base.validationexpression always fails due to it not being assigned in the constructor.
What I have is a public property that looks at the viewstate.
public NameType NameValidationType
{
get
{
return this.ViewState["NameType"] == null ? NameType.FirstName : (NameType)ViewState["NameType"];
}
set
{
this.ViewState["NameType"] = value;
}
}
This value is always null when the constructor is called. Is there some way to delay the execution of the constructor to read from viewstate before being constructed?
Thanks for any help.

My solution to get this to work is to build the controls base validationexpression and other attributes in the OnPreRender event. Render was too late and anything before the OnPreRender did not have access to viewstate.

Reference Session in Helper class

So I have a method that I "borrowed" from the internet that I use on many of my pages to handle the sorting of a grid column.
private string GetSortDirection(string column)
{
// By default, set the sort direction to ascending.
string sortDirection = "ASC";
// Retrieve the last column that was sorted.
string sortExpression = ViewState["SortExpression"] as string;
if (sortExpression != null)
{
// Check if the same column is being sorted.
// Otherwise, the default value can be returned.
if (sortExpression == column)
{
string lastDirection = ViewState["SortDirection"] as string;
if ((lastDirection != null) && (lastDirection == "ASC"))
{
sortDirection = "DESC";
}
}
}
// Save new values in ViewState.
ViewState["SortDirection"] = sortDirection;
ViewState["SortExpression"] = column;
return sortDirection;
}
Now it works great, but alas, I must copy it to every page that I want to call it from because it references the viewstate. So I want to move it to my helper class and have it store in the session state instead, however, I can referernce neither State in the helper class.
Is their any way to access the session from a help class? Can I pass by reference the session state?

If I understand the question correctly, you're looking to access ViewState or Session from a class that is not a page.
If so, you can use HttpContext.Current.Session, or, you should be able to typecast HttpContext.Current.CurrentHandler to type Page, and then access the ViewState.
Alternatively, you could always just put your code in a base class, which all your pages will inherit from, rather than inheriting from System.Web.UI.Page.

No you don't use Session, because if you test Session, you have user 1 that select One Columns 1, and he changes page, he will have the same selected columns, this is problem , becaue when use initilize page, he must have initial state and no selected state.
Technically you can use Session but for me functionaly it's not recomended

You can use HttpContext.Current.Session in any assembly which references System.Web and is executing in a web process.
However, putting generic (i.e. reused in multiple places, non-specific key) values like that in Session will cause all sorts of trouble. For example, what if the user opens two browser windows in the same session?
I would suggest either a base Page/Control/UserControl class, or a helper class which is initialized with data from the page. Your code sample looks more like it belongs in control-related base class.

You can use System.Web.HttpContext.Current however you could run into some syncing issues using session state like this. It's possible you could add your GetSortDirection method as an extension method to page which may be easier to accomplish.

Ways to share common functions betweed few pages in ASP.NET

This is possibly very lame question and I lack knowledge about ASP.Net. In this case a link to an article explaining would be very welcome.
I'm working on web-site on ASP.NET with C# as codebehind. My current project involves developing few pages with very similar functionality and a many functions are the same. For example
private void PermissionCheck()
{
if (null == Session["UserID"] ||
null == Session["ProjectID"] ||
null == Session["AssetID"] ||
null == Session["ProjectName"])
{
Response.Redirect("~/Login.aspx");
}
}
Would be the same on 2 pages. Some other things are the same as well. I would like to put this into common base class. But there are other functions that don't really belong to pages at all:
private string GetAttachmentTempPath()
{
return Request.PhysicalApplicationPath + WebConfigurationManager.AppSettings.Get("AttachmentsTempFolder");
}
I would like to move this into Attachment class, but to get the physical path of the application, I need to pass in Request object into that method, which is not really nice, as it couples Attachment class with Page.Request object.
Is there any way to move these functions somewhere else without needing to pass Page.Request objects around??
p.s. The appliction is huge, and there is no scope to change the entire architecture.

For your permission thing you could make a base page class:
class BasePage : Page
{
...
protected override OnInit() {
// do check here
}
}
Now you can implement your page like this class MyOtherPage : BasePage { ... }
The OnInit gets executed everytime your MyOtherPage gets loaded.
You can see a complete page lifecycle here: Link
For your other problem: Consider to implement a global available static tool class
Update
A good approach for making things like web.config easier to access is a Singleton. In asp.net a singleton is only created once and lives until the asp worker process gets stopped . So this values are shared across the whole asp.net application. This is also good for storing data in a global context that you dont want to get out of your database or file anytime a user makes a page request (for example a version number or things like that)
Update 2
To access the request without passing it to every function, use this:
HttpContext.Current.Request

Base page is a good option for reusable code in Page level. Other than that for things like configuration values it's good to come up with utility classes specifically for those methods base don there type of operations.
If you need to avoid passing in Page object into these types of utility methods,
HttpContext
class would be handy because you can access many of the ASP.Net object through static members through this class. HttpConext # MSDN

If you have similar functions behind the page, you can use ASP.NET WEb User Control.
You can create the functions in the usercontrol and use the control in the pages where necessary.
Have look at this article about Web User Control in Asp.Net

ASP C# How to program neat GUI code

For about a few months i'm programming ASP C#. I always program a lot code in the events and in the load event i check the querystring for valid data. This is some sample code i have in one of my projects:
protected void Page_Load(object sender, EventArgs e)
{
if (Controller.Manual == null)
{
Response.Redirect("login.aspx");
}
lblLocation.Text = "<a href='viewdocument.aspx'>" + Controller.Manual.Title + "</a>";
if (Request.QueryString["gchap"] != null)
{
if (Controller.IsNumeric(Request.QueryString["gchap"].ToString()))
{
genchap = Convert.ToInt32(Request.QueryString["gchap"]);
FillGeneralList();
SetChapterTitle();
}
}
if (Request.QueryString["qchap"] != null)
{
if (Controller.IsNumeric(Request.QueryString["qchap"].ToString()))
{
qualchap = Convert.ToInt32(Request.QueryString["qchap"]);
FillQualityList();
SetChapterTitle();
}
}
// Check document Id is set (did)
if (Request.QueryString["did"] != null)
{
if (Controller.IsNumeric(Request.QueryString["did"].ToString()))
{
docId = Convert.ToInt32(Request.QueryString["did"]);
DetermineView();
}
}
}
I know there must be a way to accomplish this on a more neat way. And this is just the load event. On other events, like click and onchange events i have similar code. I think this is spaghetti code and not well-arranged. So can you tell me how i can arrange my code?
EDIT:
What i want to know is, is there a more neat way to, let's say, fill a listbox? And where do i check whether a querystring value has valid data? Where do i check whether the (input/querystring) data is a number? And where should you put the code that validates the Querystring? Also in the load event?

I feel your pain with some of the organization issues with ASP.NET websites. I've had similar code to yours on several projects.
If you have the choice of your frameworks you might look into ASP.NET MVC. This allows you to have clear separation between the View (Html), the Controllers (All actions and business logic) and the Model (database). That way you have zero code in your codebehind files, it all stays nice and neat in controllers.

Try using TryParse (for example) and you can simplify all the code that looks like
xx.IsNumeric(Request.QueryString["qchap"].ToString())
and
Convert.ToInt32(Request.QueryString["gchap"]);
and reduce the number of calls to Request.QueryString variables
You could try something like
Original code
if (Request.QueryString["gchap"] != null)
{
if (Controller.IsNumeric(Request.QueryString["gchap"].ToString()))
{
gchap = Convert.ToInt32(Request.QueryString["gchap"]);
FillGeneralList();
SetChapterTitle();
}
}
Suggestion
int? gchap; //nullable types thanks Richard :D
if (!int.TryParse(Request.QueryString["gchap"], out id)) {gchap = null};
if (gchap != null) {
FillGeneralList();
SetChapterTitle();
}
// you could make this neater with your own little method
Have a look at this post How do you test your Request.QueryString[] variables?

Try capturing the repetitive code in a separate function. (qchap / gchap)
e.g.:
qualchap = ConvertFillAndSet(Request.Querystring["qchap"]);
genchap = ConvertFillAndSet(Request.QueryString["gchap"]);
private int ConvertFillAndSet(string qrystring)
{
int numberToReturn = 0;
//if the conversion was ok -> true, else false
if (Int32.TryParse(qrystring,numberToReturn))
{
FillQualityList();
SetChapterTitle();
}
//returns 0 if tryparse didn't work
return numberToReturn;
}

Where to start. Unfortunately despite other comments, you're not really writing anything that is 'web forms' specific. So moving to MVC isn't going to magically make your code better.
1 Don't roll your own authentication: Use forms authentication unless you have a compelling reason not to. When using forms authentication, you don't need to write code on every page to check that you're logged in. The framework handles that for you.
2 Learn to use the server controls:
Also as others write you shouldn't be writing html in code, especially for something so trivial. Web forms doesn't make you do this either.
<!-- this is in MyPage.aspx -->
<asp:HyperLink id="viewLink" runat="server" />
// in the code-behind file MyPage.aspx.cs
viewLink.NavigateUrl = "~/viewdocument.aspx";
viewLink.Text = Controller.Title;
If you're going to stick with web forms, you need to get familiar with the ASP.Net Page life-cycle
3 Your code is in need of refactoring. No matter if it's web forms, php, or MVC. Here are some basic refactorings, and none of this is really .net specific. I'll walk through these in small steps.
// this may be a good candidate for an extension method
int? ConvertNullable(string nullableInt) {
if( string.IsNullOrEmpty(nullableInt) )
return null;
int value;
if( Int32.TryParse(nullableInt, out value) )
return value;
return null;
}
which then allows you to write.
int genchap? = ConvertNullable(Request.QueryString["gchap"]);
int qualchap? = ConvertNullable(Request.QueryString["qualchap"]);
int docId? = ConvertNullable(Request.QueryString["did"]);
FillQualityList(genchap,qualchap);
SetChapterTitle(genchap,qualchap);
DetermineView(docId);
but passing a lot of primitives around is a hassle and prone to errors, so sometimes we make a small class to encapsulate the data, in this case the page initialization information.
class ChapterView
{
public int? GenChapter {get; set;}
public int? QualChapter {get; set;}
public int? DocumentId {get; set;}
}
private ChapterView GetChapterView()
{
return new ChapterView
{
GenChapter = ConvertNullable(Request.QueryString["gchap"]),
QualChapter = ConvertNullable(Request.QueryString["qualchap"]),
DocumentId = ConvertNullable(Request.QueryString["did"])
}
}
Note that I've no idea what GenChap and QualChap are, but they're a bit terse and you could complete the refactoring to make them more readable in code. But even without better names, we now have more readable code.
ChapterView chapterView = GetChapterView();
FillQualityList(chapterView);
SetChapterTitle(chapterView);
DetermineView(chapterView);
And finally you may determine that you don't really need to call this every time the page executes to read from the query string. If you've read up on the Asp.Net Page LifeCycle you know that events may change GenChapter or something else that affects how the page is rendered. You may find it better to set up the view in the PreRender instead of calling FillQualityList over and over again.
ChapterView chapterView;
Page_Load()
{
if( !IsPostback )
{
ChapterView chapterView = GetChapterView();
}
else
{
chapterView = (ChapterView) ViewState["chapterview"];
}
}
NextChapter_Click()
{
chaperView.NextChapter();
}
Page_PreRender()
{
FillQualityList(chapterView);
SetChapterTitle(chapterView);
DetermineView(chapterView);}
// make sure class is marked [Serializable]
ViewState["chapterview"] = chapterView;
}

you should follow layered approach. ie: put all your data access code in data access layer, put all your business logic (which also includes validations) in your business layer, put all your model code in your business object layer
and finally for ui - try to never generate html mark up from within the code as far as possible. also, always create a root class for your aspx pages where it has common methods already implemented. then subclass this root class for every other aspx pages
if you are going to hardcode html markup within your c# code - i can assure you this would always result in a lot of chaos (based on my own experience)
but there are situations where you simply cant avoid it. for such cases - this is what i do - i get rid of the code behind and simply put that code in my aspx / ascx file itself. that way when i have to change my ui based on never ending client requests, i dont have to recompile my code - i simply replace my aspx / ascx files on the staging / production server.
you know how clients are : hmmm can u make the black strip look a bit like gray, can u increase the spacing between lines, can u change the text of this hyper link... requests like these never seem to end :-)

ASP.Net and GetType()

I want to get a type of a "BasePage" object that I am creating. Every Page object is based off BasePage. For instance, I have a Login.aspx and in my code-behind and a class that has a method Display:
Display(BasePage page) {
ResourceManager manager = new ResourceManager(page.GetType());
}
In my project structure I have a default resource file and a psuedo-translation resource file. If I set try something like this:
Display(BasePage page) {
ResourceManager manager = new ResourceManager(typeof(Login));
}
it returns the translated page. After some research I found that page.GetType().ToString() returned something to the effect of "ASP_login.aspx" How can I get the actual code behind class type, such that I get an object of type "Login" that is derived from "BasePage"?
Thanks in advance!

If your code-beside looks like this:
public partial class _Login : BasePage
{ /* ... */
}
Then you would get the Type object for it with typeof(_Login). To get the type dynamically, you can find it recursively:
Type GetCodeBehindType()
{ return getCodeBehindTypeRecursive(this.GetType());
}
Type getCodeBehindTypeRecursive(Type t)
{ var baseType = t.BaseType;
if (baseType == typeof(BasePage)) return t;
else return getCodeBehindTypeRecursive(baseType);
}

After some additional research I found that if I call Page.GetType().BaseType it returns the code-behind type of the Aspx page.

page.GetType().BaseType, it has been said before, but let me elaborate as to why.
Aspx pages inherit from their code-behind pages, meaning that the inheritance hierarchy looks like this:
...
Page
BasePage
Login
ASP_Login
Where the top is the parent and the bottom is the child.
This allows your code behind to be accessible from the aspx page, without requiring all of the generated code related to your actual aspx page to be copied into the base class page.

It depends where you're calling Display() from. If you're calling it from the ASPX, then you'llse "ASP_login.aspx". If you're calling it from the code-behind (i.e. the Page_Load() method) you should get the Login page type.
Instead of passing the Page in, you might consider just using the Page property (i.e. this.Page.GetType()) which should always be the current page/codebehind type, if I recall correctly.
I should also make the point that you might consider moving this sort of stuff out of the ASPX/codebehind and into some sort of service. It's generally a good idea to minimize the amount of things you do in a code behind and, instead, push logic into a presenter class and follow the MVP pattern for ASP.NET Web Forms development.