_Dynamic Block Creation - Parameter Value Set

For mechanical design, we often need to stretch the keyway to a certain length. Now, let us see how to realize the accurate stretch.
1. Pick Linear Parameter:
In block editor, pick the linear parameter, then click the entry frame which is on the right side of "distance type" on the Properties panel, there comes one drop-down menu.

Therein, none is the default option, means can stretch optionally. By the other two options, you can define the maximum and minimum numbers respectively.
"Increment" means stretch increasingly, Value set appears like below after select increment.

If you choose "list", Value set appears like the below picture, the dynamic block can only be stretched accord with the number in the list.

2. Click Text Frame:
Which is on the right side of the "distance value list". Click this button, it comes "Add distance" dialog box. Add three numbers “1”.“1.5”.“2” in the dialogue box, as shown in below picture

3. Test Dynamic Block:
Exit from block editor and stretch the right grip, you will realize several gray lines appear in the right side of the keyway, and the keyway can only be stretch to the gray line position, as shown in the below picture. Obviously, by value list, you can define certain numbers of the stretch, to realize accurate stretch.