qr code c# Efficiency vs. Effectiveness in visual C#.net

Paint QRCode in visual C#.net Efficiency vs. Effectiveness

CHAPTER 6 EXTENSIBLE MARKUP LANGUAGE (XML)

Figure 5-33. A sine (full curve) and its cosine (dotted curve) For example, at the very top or bottom of your wave (where the water is flat), the cosine reaches 0, indicating the (0,1,0) vector shouldn t be deviated. At the middle of the slope of your wave, the cosine indicates maximum deviation. This means that next to taking the sine, you ll also need to take the derivative of your heights function. Since the heights function is multiplied with xWaveHeights, you ll have to do the same with the derivative function. The derivative of a sine is the cosine, while you also need to divide by xWaveLengths as dotProducts (the horizontal axis in Figure 5-33) is divided by xWaveLengths. float4 derivatives = xWaveHeights*cos(arguments)/xWaveLengths; This actually makes sense, because the higher your waves are, the steeper they are, and the more you should deviate your normal. Furthermore, the more you stretch your wave, the less you need to deviate your normal from the (0,1,0) direction.

Console.WriteLine("Finally clause executed"); // release the resources ReleaseResources(); } // wait for input before exiting Console.WriteLine("Press enter to finish"); Console.ReadLine(); } static void AllocateResources() { Console.WriteLine("Allocated Resources"); } static void ReleaseResources() { Console.WriteLine("Release Resources"); } } In this example, there are two methods that represent allocating and releasing resources: AllocateResources and ReleaseResources. There are lots of scenarios where you need to make sure to release a resource whether or not an exception is thrown. One of the most common is opening and closing a connection to a database. The AllocateResources method is called before the try statement, which would usually contain statements that use the allocated resources and that may throw an exception. In my example, I have defined, but not initialized, a local variable called myLocalVar. When the condition in the if statement is true, a statement is executed that causes a NullReferenceException to be thrown. Compiling and running the code in Listing 14-11 produces the following results: Allocated Resources Perform work... Exception: System.NullReferenceException Finally clause executed Release Resources Press enter to finish You can see that when the exception is thrown the statements in the catch clause are executed, followed by those in the finally clause. In the example, this means calling the ReleaseResources method so that any allocated resources can be released promptly for use by others. We can change the condition of the if statement to false like this: if (false) { // try to so something with the local variable Console.WriteLine("First letter: {0}", myLocalVar[0]); } The change prevents the statement that causes the exception from being executed. Compiling and running the modified code produces the following results:

(managed code only) Auxiliary Displays Sensor Nodes Health Monitoring Remote Controls Robotics Wearable Devices Dataloggers Home Automation Industry Control Vending Machines ...

When done, the user can either click the Update or Cancel links on the row. If they click Update, the UpdateObject event is raised by RolesDataSource to trigger the data update. This event is handled in the page: protected void RolesDataSource_UpdateObject( object sender, Csla.Web.UpdateObjectArgs e) { try { ProjectTracker.Library.Admin.Roles obj = GetRoles(); ProjectTracker.Library.Admin.Role role = obj.GetRoleById(int.Parse(e.Keys["Id"].ToString())); role.Name = e.Values["Name"].ToString(); Session["currentObject"] = obj.Save(); e.RowsAffected = 1; } catch (Csla.DataPortalException ex) { this.ErrorLabel.Text = ex.BusinessException.Message; e.RowsAffected = 0; } catch (Exception ex) { this.ErrorLabel.Text = ex.Message; e.RowsAffected = 0; } } This code is quite similar to that for the insert operation discussed earlier, though in this case, the specific Role object that was edited is retrieved from the collection: ProjectTracker.Library.Admin.Role role = obj.GetRoleById(int.Parse(e.Keys["Id"].ToString())); e.Keys contains all the values from the page that correspond to the properties defined in the GridView control s DataKeyNames property. Recall that the only property set in DataKeyNames was Id, so that s the only value provided through e.Keys. This value is passed to the GetRoleById() method to retrieve the correct Role object.