Normal text selection is done on a line-by-line basis; it is impossible to select parts of multiple lines with normal text selection. Figure 2-2 shows how it is not possible to select just the right side of the equals sign using normal text selection. This is a drawback that most of us have become accustomed to.
Visual Studio has a feature that allows you to get around this limitation. By holding the Alt key while selecting text, you trigger block selection, which allows you to select text regardless of what line it is on. Figure 2-3 shows how block selection can be used to select only text to the right of the equals sign.
Block selection can be used to select any amount of text in a block, as opposed to line by line. You can use block selection whether you select text with the mouse or the keyboard (hold down Alt and Shift, and press the arrow keys to perform a block selection with the keyboard).
When pasting block selections, Visual Studio will insert each line of the block onto a subsequent existing line, unlike normal selections where new lines will be inserted. Thus, it is important to be sure that the destination for your block selection is the same number of lines as the source.