Checkbox to remember data

Dear Forum members,

Recently I got this working piece of VBA code from this forum that remembers the data that a user has typed in the inputboxes on a userform so when the next userform opens the user doesn't have to type all information again.
This works great and is very usefull but I want to make a small change to this.
I made a checkbox in the userforms and now I want the data to be remembered only when the user has selected this checkbox
If the checkbox is not selected the data should not be remembered.
I tired to place the checkbox = true code on several places but it's just not working....
Can someone help me out
This is the working code that remembers the user's input

Private Sub CommandButton1_Click()
Cells(Rows.Count, 1).End(xlUp).Offset(1) = TextBox1.Text
End Sub
Private Sub TextBox1_afterupdate()
txtvalue = TextBox1.Text
End Sub
Private Sub UserForm_Initialize()
TextBox1.Text = txtvalue
End Sub

How and where should I add the code so the data is only remembered when checkbox1 is selected ??

After testing a lot and tried many options with the code, I was able to find the solution
Below is how I fixed it.

Private Sub CommandButton1_Click()
Cells(Rows.Count, 1).End(xlUp).Offset(1) = TextBox1.Text
If Me.CheckBox1 = True Then
	txtvalue = TextBox1.Text
   Else
	txtvalue = ""	
End Sub
Private Sub TextBox1_afterupdate()
txtvalue = TextBox1.Text
End Sub
Private Sub UserForm_Initialize()
TextBox1.Text = txtvalue
End Sub