ASP.NET PDF Viewer using C#, VB/NET

Yup; we re no better off than before, because all we ve done is to pass the responsibility up to the client, and they are still free to ignore our pleadings. Given that the problem is a result of our oversight in the first place, what is the likelihood that we ll remember to check the error message Things would be even worse if this was in a library; we could recompile against this new version, and everything would seem fine, while in the background everything would quietly be going horribly wrong. It is probably about time we did something with the error message, so let s see what happens in our client code (see Example 6-10).

how to convert number to barcode in excel 2010, barcode font excel 2003 free, barcode add in excel 2010 free, free excel 2d barcode font, how to make barcodes in excel 2003, excel formula to generate 13 digit barcode check digit, barcode font in excel 2003, barcode add in excel free, free download barcode font excel, excel vba barcode generator,

static void Main(string[] args) { Turtle arthurTheTurtle = new Turtle { PlatformWidth = 0.0, PlatformHeight = 10.0, MotorSpeed = 5.0 }; ShowPosition(arthurTheTurtle); // We want to proceed forwards arthurTheTurtle.LeftMotorState = MotorState.Running; arthurTheTurtle.RightMotorState = MotorState.Running; // For two seconds TurtleError result = arthurTheTurtle.RunFor(2.0); if (result != TurtleError.OK) { HandleError(result); return; } ShowPosition(arthurTheTurtle);

// Now, let's rotate clockwise for a bit arthurTheTurtle.RightMotorState = MotorState.Reversed; // PI / 2 seconds should do the trick result = arthurTheTurtle.RunFor(Math.PI / 2.0); if (result != TurtleError.OK) { HandleError(result); return; } ShowPosition(arthurTheTurtle); // And let's go into reverse arthurTheTurtle.RightMotorState = MotorState.Reversed; arthurTheTurtle.LeftMotorState = MotorState.Reversed; // And run for 5 seconds result = arthurTheTurtle.RunFor(5); if (result != TurtleError.OK) { HandleError(result); return; } ShowPosition(arthurTheTurtle); // Then rotate back the other way arthurTheTurtle.RightMotorState = MotorState.Running; // And run for PI/4 seconds to give us 45 degrees result = arthurTheTurtle.RunFor(Math.PI / 4.0); if (result != TurtleError.OK) { HandleError(result); return; } ShowPosition(arthurTheTurtle); // And finally drive backwards for a bit arthurTheTurtle.RightMotorState = MotorState.Reversed; arthurTheTurtle.LeftMotorState = MotorState.Reversed; result = arthurTheTurtle.RunFor(Math.Cos(Math.PI / 4.0)); if (result != TurtleError.OK) { HandleError(result); return; } ShowPosition(arthurTheTurtle); } Console.ReadKey();

There are times when you ll want to assign several tooltips to a single widget usually when you re dealing with views for models and other widgets showing a complex document. In these situations a single widget is used to show several different items, in which each item might need a tooltip of its own. For example, suppose you have a drawing application in which you want to use tooltips to show the diameter of circles and the width and height of rectangles. Because the entire drawing is shown using a single viewing widget, that widget needs to provide different tooltips depending on where the mouse pointer is located. To do this it helps to understand how the tooltip is shown. The actual appearance of a tooltip is triggered through a ToolTip event. By intercepting the event in the event(QEvent*) method, you can change the tooltip depending on where the mouse pointer is located. Figure 9-4 shows the desired effect: the four squares are all part of one widget, but each square shows a different tooltip text.

private static void HandleError(TurtleError result)

Now that you ve investigated the asynchronous login functionality, before you look into the rest of the functionality of Atlas, it s a good idea to create a real user. You do this by first clicking the Register tab of the Login pane (see Figure 7-14).

{ }

Console.WriteLine("We hit turtle error {0}", result); Console.ReadKey();

Every time we call the RunFor method, we have to stash away the error message that is returned, check it for problems, and then decide what we re going to do. In this instance, we decided to quit the application, after showing an error message to the user, because it isn t safe to continue. If we compile and run, here s the output:

avoiding the need to intercept the ToolTip event for the view widget or the scene. When working with item views, you can use the model-view architecture to set tooltips for each item by assigning data to Qt::ToolTipRole. If you want to provide custom tooltips for the view, reimplement the viewportEvent(QEvent*) method instead of event().

Arthur is at (0,0) and is pointing at angle 0.00 radians. Arthur is at (0,10) and is pointing at angle 0.00 radians. We hit turtle error RotateError

From an application point of view, this is much better behavior than before: we were able to stop when we hit our first problem. Unfortunately, we had to write quite a lot of boilerplate code to achieve that end, and our code is much less readable than it was before. We also created a huge number of potential exit points out of our function, which decreases its maintainability. So while it is better, I m not totally happy with it; this is catching just one potential error from one function, and we have almost as many lines of code dealing with that as we do our success scenario, scattered throughout our whole program!