How can I randomize all lines in a TextBox?

I want to randomize all lines in TextBox.Text.

But my code is randomizing the values in the array myStrings() only. What I want to do is randomize all lines in TextBox.Text.

Here's my code:

Dim myRnd as New Random
Dim myStrings() As String  = {dfasdht,agaskhga,twrtwert}

Textbox1.Text = myStrings(myRnd.Next(3))

Here's an example of what TextBox.Text should start with:

sample1
sample2
sample3

And end with:

sample2
sample1
sample3