在textbox里放按钮并控制输入字符不能覆盖住按钮(包括设计阶段)[7]

                return true

            end if

        else

            dim leng as integer = cint(me.creategraphics.measurestring(str, me.font).width)

            dim m as integer = me.width

            dim p as integer = btn.width

            if leng + 1 >= m - p then

                return true

            end if

        end if