With the cursor in the text frame, cmd or ctrl+a
Using the Selection Tool click on the text frame and then cmd + C
Um, not really...
Well technically the OP didn't ask about selecting text, he asked about selecting the content so I stand by my answer.
What are you doing with the text? Without selecting text and just selecting the box, you can edit fonts, change colors, etc. you don't always have to select the text content itself.
Kind of a stretch there since the OP clearly said he was triple-clicking to select the text.
That's only true if the frame is not threaded with others.
Yeah I know it was a stretch but since he was annoyed about having to click three times I thought I'd throw a curve ball in there.
Ok then, straight answer? With the Type Tool selected, click once in the text frame, click twice to select one word, click three times to select one line, click four times to select one paragraph, click five times to select all threaded text. It's not that big of a deal. InDesign is a very sophisticated page layout program. There are easy ways and short cuts to do some things but selecting text is not that difficult.
(I just re-read what I wrote and I want to assure everyone that I'm not trying to be an ***, I'm just slightly sarcastic, with a friendly smile!)
Have a Good Friday everyone!
In line with that, Cursor at the beginning of a line, press Shift + End to select the whole line, then Shift + Down Arrow to select an addtional line at a time. Works from the bottom up, too, Using Shift + Home to select to the beginning of a line.
Also, Ctrl(Cmd) + Shift + End/Home will select from the curren tlocation to end or start, respsctively, of a story.