The Immediate Window in C#.NET

Generator Code 3/9 in C#.NET The Immediate Window

While debugging, it s often useful to type an expression to see the results at the current time The Immediate window allows you to type in variable names and many other types of statements You can access the Immediate window by selecting Debug | Windows, or it may open for you automatically during debugging at the bottom-right side of VS You can see the Immediate window being used in Figure 6-11 The Immediate window in Figure 6-11 has three statements, showing that you can read a property, execute a method, or evaluate an expression I typed these statements in myself, and you can do the same, writing nearly any code you want When evaluating an expression in VB, prefix the statement with a question mark,

If you recall from the previous section on design-time tools, the Call Hierarchy window gives you a view of the code at design time On a related note, you also have the ability to view the path of execution during runtime via the Call Stack window During debugging, you may find the Call Stack window already open on the right-bottom of VS in a tab next to the Immediate window if you ve not changed your layout and depending upon your initial VS environment setup Otherwise, you can open this window by selecting Debug | Windows | Call Stack from the top menu bar With the Call Stack window, you can view the current execution path of the application from Main to where your current line of execution is Figure 6-12 shows the Call Stack window To understand why it s called a Call Stack, notice that each method call is stacked on the other with the current method at the top, the entry point at the bottom, and subsequent calls in between; it s like a stack of plates where the last plate is at the top In the Call Stack window, shown in Figure 6-12, you can see that I ve stepped into the GetOrderDiscount method Double-clicking another method in the Call Stack window brings you to the call site where a given method was called This is a very important and powerful tool because it allows you to visit calling code and inspect application state at the call site, giving you valuable information about how calculations were formulated before the current method was called

The Quick Watch window allows you to quickly view an expression It offers Intellisense when writing the expression, allowing you to reevaluate the expression and add the expression to a Watch window You can open the Quick Watch window by selecting Debug | Quick Watch or pressing CTRL-D, Q If you ve selected an expression in the editor,

the Quick Watch window will show that expression Figure 6-13 shows the Quick Watch window in use Clicking the Reevaluate button, shown in Figure 6-13, will show the results of evaluation in the Value area The Value area will only hold the current expression If you want to save an expression, click Add Watch, which will load the expression into a Watch window Be aware that closing the Watch window will remove your expression, but the expression will be part of a history list that you can select from

While debugging, you can hover over any variable to see its value, but when you move the mouse away, the tooltip with the value goes away The Pin To Source feature goes a step further by displaying the value all the time To use Pin To Source, right-click the variable and select Pin To Source Alternatively, you can hover over the variable in the debugger and click the push-pin that shows with the tooltip Figure 6-14 shows a pinned value Once you ve pinned a value, you can continue debugging and scroll back up to the variable to read its current value In addition to seeing the value, you can add a comment by clicking the chevron that appears when you hover over the pinned value The pinned value is commented with product of discount and sum of order items