Set the Selection property of CompletionSession.

I want to set the current selection of auto-complete in this way.

Even if the value of CompletionSelectionState is set to Full, the selection will only scroll to the target position. And did not choose it.

The effect I want is after setting the Selection property. Ability to trigger commit directly through the commit character.Instead of pressing the arrow keys to commit.

Is this because of what attributes I set that causes it not to be selected automatically?

this.Selection = new CompletionSelection(selectItem, CompletionSelectionState.Full);