Examining a Variable or Expression

Examine how a variable or expression is resolved in the debugger.

Use one or more of these methods to examine variables and expressions. Unless otherwise noted, the methods are available only after you start the debugger and break execution:

Place the edit cursor over a variable in a Script window to display its DataTip.
The DataTip shows information about the variable in its current scope. If the underlying identifier is a data structure, the DataTip shows a tree that you can expand to view its members and the values of its properties. You can also see the values of variables, but you cannot change values in the DataTip. The DataTip closes when you remove the cursor.
See the Visual Studio help for information about using DataTips.
Use QuickWatch to see the current value of a single variable or expression. Select Debug > QuickWatch, or right-click in the Script window and select QuickWatch.
See the Visual Studio help for information about evaluating expressions in QuickWatch.
Use the All Variables window to see global, shared, and instance variables that are in scope. The window is usually open during debugging, but if necessary, you can manually open it by selecting Debug > Windows > All Variables.
Use the Autos window to see variables used in the current line of code and the preceding line of code. This window is also usually open during debugging, but you can manuyally open it by selecting Debug > Windows > Autos .
Use visualizers to examine the contents of data. Visualizers are represented in a Datatip or variable window by a magnifying glass icon. You can click the icon to see its DataWindow or ListView visualizer.
Create as many as four Watch windows to store variables and expressions to evaluate during the debugging session. To open a Watch window, select Debug > Windows > Watch > Watchn .
See the Visual Studio help for information about evaluating expressions in the Watch window.
Change the value of a variable to see its effect on execution:
1. Right-click a variable in a DataTip, a variable window, or the Watch window, and select Edit Value.
2. Change the value.
The new value must conform to the type of the variable. If the variable is a string, do not enclose it in quotes. You cannot change the value of an enumerated variable.
You might want to change the value of a variable to examine different flows through the application, to simulate a condition that is difficult to reach in normal testing, or if you are skipping code that sets a variable's value.
The new value is used when you continue execution.
Use the Immediate window at design time to evaluate variables or expressions during debugging, or to execute commands, functions, or subroutines at design time. To display the Immediate window, select Debug > Windows > Immediate.
See the Visual Studio help for information about using the Immediate window.

Notes: Variables that are declared. or declared and initialized, but not used in a .NET application are discarded when the application is deployed to .NET. As a result, information about unused variables does not appear in the debugger.

Backslashes (\) in expressions appear as double blackslashes (\\) in QuickWatch, DataTip, and Watch windows. The first backslash is an escape character. It indicates that the second backslash is text in the script rather than a control character.