Archive for WebForms tag
Investigating MonoRail
Fighting WinForms
I hate fighting with a technology to get it to do what I want because it means I either have the wrong expectation or wrong technology.
With web development I expect strict web standard support and clean code that is easy to maintain.
I am, therefore, tired of fighting with WebForms and seeing as I’m not prepared to change my expectation then the technology must change.
Looking at MonoRail
Ruby on Rails is very fast, elegant and powerful but comes with a bunch of unknowns. The IDE’s I’ve tried have been so-so, there is no support for IntelliSense so I’m forced to remember exact property and method names. There are concerns about performance and scalability and I find the Ruby language itself cryptic.
My current .NET environment has all these things, so what I’m really looking for is an alternative to the WebForms element itself. It also has a powerful framework, tons of samples, and C# is not only enjoyable but very in-demand :)
MonoRail seems to be just what I am looking for but there are a number of things keeping me away. I decided to spend an hour watching a screen cast on WinForms and MonoRail from Ayende @ Rahien’s blog. It calmed some concerns but raised a few others…
NHibernate mapping files
NHibernate provides the core ORM system within MonoRail and normally requires XML mapping files to do so.
I really don’t want or need another abstraction layer here – my tables are freshly modeled and represent my domain classes very well. Rails, Subsonic and LINQ to SQL are all happy to just do it/
Thankfully a project called ActiveWriter gives you a very LINQ to SQL-like experience in dragging tables off, changing names and properties if you want and doing the magic for you.
ActiveRecord template
I still don’t like this mix of static and instance methods providing some sort of split between what should really be two classes but I can live with it.
There is also a Repository<T> option mentioned which perhaps solves this, I shall have to investigate it further.
View engines
There are a number of view engines available for MonoRail but the primary ones are NVelocity and Brail.
As I already have C# and JavaScript in my project and I have no desire to add another language unless there is a good reason to do so. If they want to stop people writing too much view code then what is wrong with a subset of C#?
The template engines also mean giving up strong typing (everything is passed to the view in a type-less property bag accessed with a string key!) and a complete lack of IntelliSense (the demo stalls as fields are mistyped on occasion proving just how useful this is).
HTML injection
Yes, in this day and age HTML injection should be a long-dead concern and yet even the built in SmartGridComponent will happily squirt out data without encoding it and thus allowing data from anywhere to contain HTML ready to be injected into an unsuspecting page.
Ayende has investigated the issue now and is working on getting a fix into the tree.
[)amien
Localizing .NET web applications
It seems that globalisation often makes the wish list of many a web site until the client realises professional quality translations require a significant investment of time and money.
On occasion however smaller web applications with their limited vocabulary are prime targets for localisation, globalisation and it can be quite feasible to translate the couple of hundred strings involved.
Here’s a very brief whirlwind overview of what’s involved.
Create the default language resource file
Create a new folder inside your App_GlobalResources folder to contain your language resource files. Then create a new resource file (e.g. Localisation\Language.resx) to use when no translation exists for the user’s preferred language.
Detect the user’s browser settings and switch
In .NET 1.1 this required a couple of lines of code in your global.asa.cs:
public void Application_BeginRequest(object sender, EventArgs e) {
Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(Request.UserLanguages[0]);
Thread.CurrentThread.CurrentUICulture = new CultureInfo(Request.UserLanguages[0]);
}Update
Sander Rijken points out that .NET 2.0 lets you do this with a line in your web.config’s <system.web> section instead:
<globalization culture="auto" uiCulture="auto" />or indeed at individual page level with:
<@ Page ... Culture="auto" UICulture="auto">Localise the classes
For every bit of code that sets a string that will end up on the user’s display you now have to move that into the language resource file and replace the code with a reference to it. So if for example you had;
if (name.Length == 0) error.Text = "Please enter a name";Then you move “Please enter a name” into the resource file and give it a sensible key such as NameBlankError and modify the above line to read;
if (name.Length == 0) error.Text = Resources.Language.NameBlankError;There is a Resource Refactoring Tool to do this for you now! Just right-click the string, choose Extract to resource and fill in the blanks.
Localise the pages
Unlike the WinForm designer the WebForms one doesn’t support multi-language so you’re instead forced to do it by hand. One way is to remove all the text from the page and place it into the resource language file.
Then create a private void Localise() method in each page that simply looks something like;
public void Localise() {
Title = Resources.Language.LoginPageTitle;
loginButton.Text = Resources.Language.LoginPageLoginButton;
reminderButton.Text = Resources.Language.LoginPageReminderButton;
}Obviously you need to call this from the page, I find that calling it from Page_PreRender works a treat.
One disadvantage to this technique is your page itself ends up looking very blank in the designer or duplicates text that soon gets out of date. You could avoid this by leaving the default-language text in the page and not calling localise if you are running in that language. Be sure to put “***” or something in the default language resource file for it though so that if it’s missing for other languages you immediately spot the missing text during testing.
Don’t treat types as strings
If you have a number, treat it as a number and pass it around as a number. The same applies to dates etc.
If you need to pass over to SQL etc. then use a parameterised query, they’re fast and will take care of all the regionalisation stuff for you!
To get those pesky strings in and out of the correct types see the following extra steps!
Always use .ToString() to format output
Almost all basic .NET types include locale-aware formatting and so keep an eye on the ToString methods. Remember even numbers are formatted differently across the globe. 1,234.00 in England and the US becomes 1.234,00 in various parts of Europe.
Be very careful of outputting currencies. .NET won’t convert the amount for you but you could easily find yourself with the wrong currency symbol and therefore a totally different price!
Always use .TryParse to read input
When accepting information from users hand over that string to TryParse for it to try and work out what’s going on. It will helpfully return a boolean indicating if it did the job okay – if not time to use that localised error-message.
Auf wiedersehen!
[)amien
Extending GridView to access generated columns
ASP.NET’s GridView is a useful control and one of it’s best features is it’s ability to generate the columns automatically from the data source given.
The problem however is that these generated columns are not exposed as part of the Columns collection or indeed available at all so you can’t hide or manipulate the selected columns.
One simple scenario might be that you want the first column to be a “View” link to drill down into the row displayed. Whilst you can add the column to the GridView before data binding you can’t actually pull out the information needed from another columns to construct the URL.
By sub classing GridView you can obtain this functionality with some caveats.
Version 1: Auto generated columns added to the Columns collection… with caveats.
using System;
using System.Data;
using System.Collections;
using System.Web.UI.WebControls;
public class GridViewEx1 : GridView
{
private DataControlFieldCollection originalColumns;
public GridViewEx1() : base() {
}
public void RecordColumns() {
originalColumns = new DataControlFieldCollection();
foreach(DataControlField column in Columns)
originalColumns.Add(column as DataControlField);
}
public void ResetColumns() {
if (originalColumns == null)
RecordColumns();
else {
Columns.Clear();
foreach(DataControlField column in originalColumns)
Columns.Add(column as DataControlField);
}
}
protected override ICollection CreateColumns(PagedDataSource dataSource, bool useDataSource) {
ResetColumns();
ICollection generatedColumns = base.CreateColumns(dataSource, useDataSource);
foreach(DataControlField column in generatedColumns)
if (!originalColumns.Contains(column))
Columns.Add(column as DataControlField);
return Columns;
}
}This version provides some compatibility with existing code/expectations in that the autogenerated columns are part of the Columns collection after the DataBind.
Should you call DataBind again however as well as wiping out the changes to the generated columns (they are, after all re-generated) any additional columns added to the collection after the first DataBind will also be lost as it does not track which are added by the programmer and which automatically.
Version 2: All bound columns exposed as BoundColumns, user ones as Columns.
using System;
using System.Data;
using System.Collections;
using System.Web.UI.WebControls;
public class GridViewEx2 : GridView
{
private DataControlFieldCollection boundColumns = new DataControlFieldCollection();
public GridViewEx2() : base() {
}
public DataControlFieldCollection BoundColumns {
get { return boundColumns; }
}
protected override ICollection CreateColumns(PagedDataSource dataSource, bool useDataSource) {
ICollection generatedColumns = base.CreateColumns(dataSource, useDataSource);
BoundColumns.Clear();
foreach (DataControlField column in generatedColumns)
BoundColumns.Add(column as DataControlField);
return BoundColumns;
}
}After the DataBind you will have full access to the generated columns as part of the BoundColumns collection.
[)amien