The holograms are here!

A while ago I wrote this entry about an innovation in sound technology that will probably change the way we think of sound.

Today I am presenting a video technology I witnessed at the mall! Yes, the mall, that dreaded place of overpriced junk and overdressed bimbos. Overpriced, too! :) Anyway, I was watching this Pepsi commercial on a big TV like device, where a can of Pepsi was rotating showing its full cylindrical glory. Only that it felt out of focus. My eyes were kind of sore watching it. Immediately the image changed to a ball that came towards the screen and then... went through the screen!

It worked from almost every angle, without being a holographic thing in the middle of the air, but more of an optical illusion. Thinking of the faithful thousands of people reading this blog every day, I remembered the little link on the side of the device: www.x3d.com, with their device called MultiView.

The image is not as clear as one would want. It's like continuously vibrating or something like that, but the optical illusion is great! I saw people passing by the device and trying to put their hand through the "flying" objects.

Here are a few links from Wikipedia about the subject:
Volumetric Display
Autostereoscopic

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How to put a databound ComboBox in a Column of a Datagrid

I found this little page while searching for a DataGridDropDownListColumn for NET 1.1 Windows Forms. It works and seems elegant enough.

To bind the column values, use column.myComboBox.DataSource, DisplayMember and ValueMember.

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The Portughese restaurant Fado

Update: I've heard that Fado has now been closed. It was nice while it lasted. Too bad I didn't have the chance to go again a few times before it went away.


Today we went with my parents at a Portuguese restaurant called Fado. I have to say I was pleasantly surprised by the cuteness of the place and the service was not bad. The food was bravely innovative, too, and tasty. Actually, it was more on my own taste than most of the restaurants I've been to, including Chinese. Well, I like Chinese more, but I can't cook Chinese, that's what I meant :-P

Anyway, if you happen to search for an intimate restaurant in Bucharest, with interesting food and a waiter that knows suspiciously much about the food, up to the point where he recommends you what is better than your original idea, then Fado is the place for you.

This is a link, in Romanian, with more details: Restaurant Fado

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Saving Page ViewState out of the page!

If you look for solutions to get rid of huge ViewStates from your pages you will get a lot of people telling you to override SavePageStateToPersistenceMedium and LoadPageStateFromPersistenceMedium in your pages and do complicated stuff like keeping the ViewState in the Cache or in a database, calculating strange keys, etc.

No more! Net 2.0 has something called a PageStatePersister. It is an abstract class and every Page has one. In case no override occurs, the default is a HiddenFieldPageStatePersister, but you can also use the provided SessionPageStatePersister like this:

protected override PageStatePersister PageStatePersister
{
get
{
return new SessionPageStatePersister(this);
}
}

And that's it! It works with Ajax and UpdatePanel, too.

However, this is no "Silver Bullet", as the SessionPageStatePersister will have issues with multiple windows open with the same session (like pop up windows) as exampled in this nice article. Also check out this situation when, during Ajax callbacks, a full ViewState is returned due to the ever troublesome ImageButtons.

There is no reason not to create your own PageStatePersister, though. The abstract class is public (not internal and sealed as Microsoft likes their most useful classes) and you can inherit it. You can even store the state in the Cache! :)

A very comprehensive article on ViewState is here.

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Buggy DataTable Select strikes again: Safe Filtering without Sorting

A while ago I wrote a post about the bug in the DataTable.Select method with columns with comma in their names.

Today I discovered another bug, when using DataTable.Select with an empty sort string, but not an empty filter string, there is an implicit sorting by the first column. Short example: a DataTable with a single column called "words" containing values c,b,a,d , when Selected with a filter like "words is not null" and a null or empty sort string, will return a,b,c,d.

The only solution for this was to drop DataTable.Select entirely and use DataView, with its NET 2.0 method DataView.ToTable. So the code to take a DataTable and return the filtered and sorted table would look like this:

public static DataTable Select(DataTable table, string filter, string sort)
{
    if (table == null) return null;
    var dv=new DataView(table);
    dv.RowStateFilter=DataViewRowState.CurrentRows;
    dv.RowFilter = filter;
    dv.Sort = sort;
    return dv.ToTable();
}

But DataView has the same problem with columns with comma in their names. We solve it in the same way we solved it in the previous post: we change the column names, the sort and filter strings, we select, then we change the column names back:

public static DataTable SelectSafe(this DataTable table, string filter, string sort)
{
    var originalColumnNames = new Dictionary<string, string>();
    
    foreach (DataColumn dc in table.Columns)
    {
        if (dc.ColumnName.IndexOf(',') > -1)
        {
            var columnName = dc.ColumnName;
            var safeColumnName = columnName.Replace(",", ";");
            var  reg = new Regex(Regex.Escape("[" + columnName + "]"), RegexOptions.IgnoreCase);
            dc.ColumnName = safeColumnName;
            if (!String.IsNullOrEmpty(filter)) {
                filter = reg.Replace(filter, "[" + safeColumnName + "]");
            }
            if (!String.IsNullOrEmpty(sort)) {
                sort = reg.Replace(sort, "[" + safeColumnName + "]");
            }
            originalColumnNames[safeColumnName] = columnName;
        }
    }

    var newTable = Select(table, filter, sort);

    foreach (KeyValuePair<string, string> pair in originalColumnNames)
    {
        table.Columns[pair.Key].ColumnName = pair.Value;
        newTable.Columns[pair.Key].ColumnName = pair.Value;
    }
    return newTable;
}

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Newest video from Linkin Park - What I've Done

At first I thought it wasn't Linkin Park singing. The sound is a bit different, at least in this song. But I like it. I hope this new album of theirs, Minutes to Midnight, will be as good as their first.

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Visual Studio 2007 (Orcas) Beta 1 released

There is an article here that explains it better than I would. Basically, the new Visual Studio is finally released in beta and is supposed to be the IDE for .NET and Vista.
The .NET Framework 3.5 (that is 2.85 in normal versioning? :D ) is also to be released here.

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