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WriteLine is another member of Console, which performs the same functions as Write, but appends a newline character to the end of each output string. For example, if you use the preceding code, substituting WriteLine for Write, the output is on separate lines: System.Console.WriteLine("This is text 1."); System.Console.WriteLine("This is text 2."); System.Console.WriteLine("This is text 3."); This code produces the following output in the console window: This is text 1. This is text 2. This is text 3.

ShowWinPart(part) Exit Sub End If End If Next ' the resource wasn't already loaded ' so load it and display the new winpart Using busy As New StatusBusy("Loading resource...") Try AddWinPart(New ResourceEdit(Resource.GetResource(resourceId))) Catch ex As Csla.DataPortalException MessageBox.Show(ex.BusinessException.ToString, _ "Error loading", MessageBoxButtons.OK, _ MessageBoxIcon.Exclamation) Catch ex As Exception MessageBox.Show(ex.ToString, _ "Error loading", MessageBoxButtons.OK, _ MessageBoxIcon.Exclamation) End Try End Using End Sub The code to find an existing ResourceEdit user control for this resource loops through all the controls hosted in the Panel control. Those items that are of type ResourceEdit are checked to see if the Resource object they are editing has the same Id value as the one just selected by the user. Assuming no matching ResourceEdit user control is found, the requested Resource object is loaded from the database. This object is passed to a new ResourceEdit user control, which is displayed in MainForm: AddWinPart(New ResourceEdit(Resource.GetResource(resourceId))) Any exceptions are handled so that the user is notified about the problem; otherwise, the user is free to move ahead and view or edit the Resource object s data.

// try to parse a string that doesn't contain a numeric value string myBadString = "Hello"; try { int myBadInt = Convert.ToInt32(myBadString); } catch (FormatException) { Console.WriteLine("Cannot parse {0} to an int", myBadString); } // wait for input before exiting Console.WriteLine("Press enter to finish"); Console.ReadLine(); } } In Listing 26-1, I perform a series of different type conversions using the Convert class. If a conversion can be performed, the ToXXX method returns the value specified by the parameter by using the target type. You can see this happening when I convert from an int to a long:

managed type. There is even a conversion from an array<T^, n> to <Object^, n>. This behavior is called covariance. Covariance does not apply to arrays of values. Although there is also an implicit conversion from a managed value to Object^, there is no implicit conversion from a value array to an array<Object^>^. The implicit conversion from a managed value to Object^ performs a boxing operation. Extending such a cast for the array would require creating a new array in which every element is a boxed object. To cover arrays of value types as well as arrays of tracking handles, the type System::Array can be used. There is also no implicit conversion from an array<Object^>^ to an array<String^>^. On the one hand, this is quite obvious, because there is no implicit upcast from Object^ to String^; on the other hand, upcasting all elements of an array is often needed in the real-life code. The for each loop can often provide a solution to this problem, because it implies a special type-safe cast for each iteration. (It is called safe cast, and will be explained in the next chapter.) The following code is legal, but the implicit casts may throw a System:: InvalidCastException when the current element of the arrObj array cannot be cast to String^: array<Object^>^ arrObj = GetObjectArrayFromSomewhere(); for each (String^ str in arrObj) Console::WriteLine(str);

The following class contains a method that uses the out keyword as a modifier for a parameter: class Calculator { public void CalculateSum(out int result, int x, int y) { result = x + y; } } The out keyword must also be used when calling a method with an out parameter, as demonstrated by these statements: // create a Calculator object Calculator calc = new Calculator(); // define a value-type variable that will be used as the ref parameter int result; // call the CalculateSum method calc.CalculateSum(out result, 10, 10);

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This section provides a step-by-step method to analyze CBC latch contention. The steps are listed in what is usually the most logical order, but they can be switched around to fit the situation at hand.

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When comparing most reference types for equality, only the references are compared. If the references are equal that is, if they point to the same object in memory the equality comparison is true; otherwise it is false, even if the two separate objects in memory are exactly equivalent in every other respect. This is called a shallow comparison. Figure 8-4 illustrates the comparison of reference types. On the left of the figure, the references of both a and b are the same, so a comparison would return true. On the right of the figure, the references are not the same, so even if the contents of the two AClass objects were exactly the same, the comparison would return false.