wParam,Specifies the starting character position of the selection. lparam,Specifies the ending character position of the selection. 但我在textbox中好象只有第一个参数起作用，第二个参数设了好象没用，从wparam指定的位置开始向后全部选定？

Combo boxes are a standard part of most user interfaces. See how you can make this old standby easier to use with a little help from the SendMessage API. You try to build various conveniences into ...