3D Desk

Well, I got to use my editor at work today. They needed a graphic of an 8 x 10 cubicle for our case managers. Kakoa, our Visio guru was out today, and so I gave it a go with my new editor. I didn't have much time to do the modeling but it turned out okay. I added a little shadowing in Photoshop but that was about it.

Happy Coding!
Jas

SQL Views with an ID column

I was recently given the task of replacing a table with a view and this table had an id column. There is a way to represent this id column in a view.

The following article explains the way to handle it:
http://support.microsoft.com/kb/186133

Keep in mind the limitations of this approach. Your row count can't be that large. If you have a large set of data and can use snapshots, consider using a temp table filled periodically for reporting. This will improve your query size and enable additional indexes if you require them.

Happy Coding!
Jas

SQL Case Statement Where? Use the "Dataman Maneuver"

Lets say you have an ice cream application. And you have two tables. One for storing the base ice cream and another for storing the actual flavors that are offered by the store. Your tables would have the following data:



Next, lets say that you have a dropdown for the base ice cream type which stores as its value the bid. In addition, one of the options is "ALL" with a value of "0." How would you write a query that will give you the rows from tblFlavors?

In VS.NET 2.0 you can add parameters to your selectcommand in the sqlDataSource control. Then, you can configure the parameter to get the value from your dropdown box. But, you have to do some work on the query to get this to work... Enter the Case statement in the where clause. Also known ast the "Dataman Maneuver" by certain trekky programmers with the initials of CRJones. :) You can visit Charley Jones at http://crjones.com


At first attempt you might try:
SELECT * FROM tblFlavors f
WHERE f.bid = @bid

This would work, but what would happen when you select the "All?" You wouldn't get any rows. You don't have any rows with a BID of 0. Enter the power of the Case statement in the where clause.

When you take a look at the where clause above, the WHERE clause is comparing the value of the bid for each row to the parameter @bid. This is a boolean operation. It is either true or false. All it cares about is whether the variables on both sides of the operator are the same datatype and that it can compare them. So, this allows us to do some crazy things with cases.

Lets try something else:
SELECT * FROM tblFlavors f
WHERE (Case when @Bid = 0 then 1 else 0 end) = 1

In this statement what are the two variables that are being compared? The right side is a 1, and the left side is whatever my case spits out. The database is smart enough to execute the case first and then compare the result against your 1. If you were to run your application, it would only work when you selected the "All" option. If you selected another option such as Vanilla, you would get nothing because @Bid would be = to 1 and in the above 1 isn't 0 so it returns 0. 0 doesn't = 1.

The solution is:
SELECT * FROM tblFlavors f
WHERE (Case when @Bid = 0 then 1
when @Bid = f.Bid then 1 else 0 end) = 1


Here it will check the first statement.
Does @Bid = 0?
yes: return the 1.
no: check the next one.
Does @Bid = f.Bid?
yes: return the 1.
no: go to else which returns 0.

Now, it checks the case value to 1 and if this is true you get your row.

Happy Coding

Cool Controls: Custom Validators

Custom validators are pretty cool to use in ASP.NET 2.0. There are quite a few samples on the web for getting these hooked up. However, most of the samples are REALLY simple in the client-side script. I wanted to throw this one out there just in case someone else has to do something similar.

The Sample:
Lets say you have a checkbox and a DropDownList, and you want the DropDownList to have validation on it only when the checkbox is checked. When the checkbox is not checked you want the DropDownList disabled. Okay, sounds pretty simple, but can we do it without a postback.

Toggling the Disabled property
The JavaScript to toggle the DropDownList disabled property can be done like so:

<script type="text/JavaScript">
function Change(chkfield,field)
{
if (chkfield.checked == true)
{ document.getElementById(field).disabled = false; }
else
{ document.getElementById(field).disabled = true; }
}
</script>

Notice that I'm passing in the checkbox object and the field to be disabled. The DropDownList will be called "dd1."
In the checkbox you just plug in the function like so:

<input id="chk1" title="chk1" onclick="Change(this,'dd1')" type="checkbox" value="X" name="chk1">MyCheckBox

Adding the CustomValidator
Next we add the CustomValidator control after the checkbox. The code would like the following:

<asp:CustomValidator
ID="CustomValidator1" runat="server" ClientValidationFunction="Checkit" ControlToValidate="dd1"
ErrorMessage="Required Field" Font-Size="Large">*</asp:CustomValidator>

With the CustomValidator control you can supply a "ClientValidationFunction" that will be called. Remember to provide a server-side function as well because if you don't it can be a security risk according to Microsoft. For this example I left that out.

The Validation Function
The validation function, called "Checkit" in this example, will check the validation of the DropDownList "dd1."

This function would look like this:

function Checkit(sender, args)
{
if(!document.getElementById(sender.controltovalidate).disabled && args.Value=="bad")
{
args.IsValid=false;
}else{
args.IsValid=true;
}
}

Notice that the function is checking for a value of "bad" in the args.Value. The CustomValidator doesn't like having null values in there so just put the word "bad" in the value of your empty selector item in the dropdownlist. There was a hack for getting this to work with null values but for this example this should do nicely.

Anyway, that's it for the Custom Validator control. Another cool control in the ASP.NET arsenal.

Happy Coding!

DX Jas

Problem stretching images with GDI+

I've noticed a problem when trying to zoom in on an image using the DrawImage method. The above image shows the problem. Basically, if you scale the image, the first row and column doesn't get scaled correctly. I've posted the problem twice on Expert-Exchange but have not found an explanation or fix yet.

I created a test app that takes a 40x40 bitmap with a checkerboard pattern and zooms it by a zoomfactor. The render code is as follows:

Protected Overrides Sub OnPaint(ByVal e As
System.Windows.Forms.PaintEventArgs) Try

If (bmp Is Nothing) Then

Else

Dim g As Graphics = e.Graphics()
g.SmoothingMode = Drawing2D.SmoothingMode.None

g.InterpolationMode = Drawing2D.InterpolationMode.NearestNeighbor
g.SmoothingMode = Drawing2D.SmoothingMode.None

Dim rect As New Rectangle
rect.X = 0
rect.Y = 0
rect.Width = (bmp.Width * m_ZoomLevel)
rect.Height = (bmp.Height * m_ZoomLevel) 'attribute shows that destination rect is
the right size but not needed for test.

Dim attr As System.Drawing.Imaging.ImageAttributes
attr = New System.Drawing.Imaging.ImageAttributes()

attr.SetWrapMode(System.Drawing.Drawing2D.WrapMode.TileFlipXY)

g.DrawImage(bmp, rect,0, 0, 40, 40, GraphicsUnit.Pixel, attr)
attr.Dispose()

End If
Catch ex As Exception
MessageBox.Show("ouch")
End Try
End Sub

This bug has been posted to Microsoft and confirmed by other programmers. A fix is to do the following:

Use (-0.5 + 0.5*srcw/dstw, -0.5 + 0.5*srch/dsth) as the source origin.

Happy Coding!
Jas

A buggy lesson

Two nights ago I was laying in my bed just about to fall asleep when I thought I heard a bug trying to fly in my ear. I jumped out of bed, turned the light on and couldn't find him. Finally I went back to bed after not finding the bug and just as I was approaching dreamland, I thought I heard the bug again. This happened several times during the night.

At some point, I started questioning my sanity. I thought maybe my brain was making up sounds that weren't there. Or, maybe my years of loud music had caught up with me and this was some sort of hearing damage.

(There is a coding point to this...) In the morning, I had two gigantic goose egg bites on my right arm. AHA! there was a bug.

At this point, I knew there was a bug and I had to find it. To make a long story short, two nights later and 6 bites total and I caught the bugger!

The moral of this story:
1. When writing programs never give up on a bug.
2. If you can't reproduce it or find evidence of the bug, don't let it drive you insane because it can. Take some time away from it and go back later. In time, you'll be able to isolate it.
3. Where there is one bug, there are usually two. Remember that unit testing can help but the test can only check logic that you coded for. Review your code change at another time you may spot others. (Yes, there were two mosquitos! I found one on the same wall 5 minutes later!!)

Happy Coding!!

My Geometry Editor

I've been working on my own geometry editor now for about a year. Its written in C# vs.2005. I should be ready to push out a beta version of it in a few months. The image is one I did on the weekend.

Development has really slowed since my second son Bryce was born in February. I'm just starting to get some work done on it now. I've been working on the rotation gizmo for the last few days. I have it working pretty well now.

What I'm looking for are beta testers or hobbyists who would like to use it on a project. It will output .X files but I can create other outputs as well if needed. Please post a reply if you're interested and describe the project you would like to work on. Its okay for low poly objects but not so great for organic objects yet. It has pretty limited tools. I'll keep posting my progress as I go.

Table vs CSS layout for forms

Separating layout elements from your information is an essential element in web design. But when it comes to form design, sometimes its quicker to use the tables.

For example, I've done the last three web forms (10-30 fields) using CSS layout. They look good, but they took twice as long to write all the css to align the items in different patterns. What am I saving here? Were the styles reusable? Not really.

Lets face it we aren't going to be changing the entire look of our input forms. The page itself? Maybe.

Even in Eric Meyers CSS book he used tables for the input forms examples.

So in conclusion:
Styles for layout: Good.
Styles for forms: Think about designing around the table.

Jas

Docking in VS.NET 2005

I was looking for a quick way to solve a docking issue in dotnet and I stumbled across this blogsite on cranky programming.

http://crankydotnet.blogspot.com

The title is "Is anyone doing anything HARD with .NET?
I thought he was right on the money. I would say the answer is "We are NOW!"

VS.NET 2005 promised to make our life easier and that actual code is greatly reduced. But, what they don't tell you is the saved coding time is reallocated to trying to tweak their controls to do what you want. And they make it look so easy in the demos...

I've reported 3 bugs I've found already with VS.NET 2005. The above link has some more. It makes me want to jump ship to the Java camp, but that's not what pays the bills.

The items I found were:

1. ASP.NET: If you comment out a control in the html view of a web form and create a new control with the name of the old one, the compiler still picks up the commented control and lists an error. On Microsoft's website it says its designed this way.

2. ASP.NET: The Textbox control "MaxLength" property does not work if "Multiline" is set to true. Again, by design..... Yeah right.

Bug workarounds:
1. VB.NET: If your design view for a form refuses to display, showing a list of variables missing you know are in place, simply hit F7, go to anyword hit spacebar and then backspace and hit F7 to return to designer. It amazingly figures out that the missing variables DO exist.

Hope this helps someone.