One of the most attractive things about Bing Crosby as a performing personality was the way he transcended and even defied the prevailing show-biz definition of success. Crosby wore fame like a cardigan sweater; lightly, looslely and without hauteur.

Now that he is gone, he is unfortunately subject to the homage of those who hew to the show-biz party line and who may suffer the error of being much more awed by Bing's fame than Bing ever appeared to be. Even so, "Bing: His Life and Legend," ABC's two-hour documentary and musical tribute at 9 o'clock tonight on Channel 7, could have been a lot gushier and moonier than it is. While entirely worthy of its enduringly elusive subject, the program is at least no insult, and it stirs memories and warm emotions without stooping to the flagrantly mawkish.

The film traces Bing's life and work through film clips, both public and private, and reminiscent intervies with everyone from the Crosby family butler ("I didn't like his singing . . . I like him because of his humble, unassuming way") to Ella Fitzgerald ("Oh, I just used to wait for those low notes!"). Fred Astaire, Mary Martin, Grace Kelly and, naturally, Bob Hope (caught on a golf course) also recollect.

In addition to some familiar footage, the program includes such rarities as Bing's screen test, in heavy makeup, for a film biography of Will Rogers that he never made, and a clip from an early three-strip Technicolor short in which he looks as round and rosy as a setting sun. One can watch the boyish bravado - and the striving a little too hard for effect - turn into irresistible pacific geniality.

Narrator William Holden, unfortunately given one of those future tense documentary scripts ("Radio will turn Bing into a national phenomenon" - it will?) falls into the traps of overstatement, but the Crosby we see on film, good sport and good sportsman, always refutes psychoanalysis by members of his families and colleagues, but it is kept within bounds and not allowed to complicate the picture we keep in our minds.

Two of the best sequences on the program have Crosby's voice serenading and soothing the nation in times of crisis; he sings "Pennies From Heaven" over newsreel film of people suffering the Great Depression and "I'll Be Seeing You" over the partings and reunions during World War II.We could count on Bing.

Crosby perfected the definitive intimate singing style for radio - for an age of new proximities between performers and their audience - and his career paralleled the rise of broadcastings as America's chief source of entertainment. Time and space were altered between forever and so was the distance between us and our starts. Crosby was one of the few who lived a life that could survive this revolutionary familiarity unscathed.

"Here comes Bing!" shouts a shapely chorine in a 1931 movie, and several decades later we find Bing joined by the likes of Louis Armstrong, the Mills Brothers, Jack Benny and Jimmy Durante on some of his television shows. With guest Maurice Chevalier, Crosby sings a revised lyric to Rodgers and Hart's "I Wish I Were in Love Again," and Chevalier at one point exclaims, "Hey Bing - I'm like spring again!"

He did have that effect. And it's easy to remember.