How can I select all the keyframe for an object or many objects?

Question

Example 1:

I have object selected. How to select all the animation keyframes for that object?

Example 2:

I have 10 objects selected. How to select all the keyframes for all the 10 objects?

Goal:

I am to copy objects from one blender file to another. I want to keep the animation for the object but I want animation to happen at different time. So I need to select all the keyframe at once so I can grab them move them all at once.

Problem:

I cannot select the keyframe one by one, it would take too long. I cannot box select all the keyframe because there are too many objects (would take many pages of scroll down and box select) and cannot be selected on one screen. Plus the box select does not work good in dope sheet view. Even if you put the box around all the diamonds, it will not select all the diamonds in the box area. It will only select some diamonds. I have proof:

But this is beside the point. I want to select all keyframe for one object or for many object.

Answer 1

I believe I found a close answer. Since Google was no help, I click on all the buttons. I found butted that looks like mouse pointer on dope sheet bar and it is called "Only incude channels relating to selected objects" and if you click that you will only see keyframe for selected object or objects. So if you select object first then click button you can then select all and only get the keyframe for selected object or objects. If no one post a better answer in couple days I will select this as the answer.