How to only use value from textbox if value exists

Hi. I have a document where i use textboxes from a userform to write to bookmarks in a word-document.
This is the code that run when i click a button:

If ThisDocument.Bookmarks.Exists("BM_Fastighetsbeteckning") = True Then
Dim BM_Fastighetsbeteckning As Range
Set BM_Fastighetsbeteckning = ThisDocument.Bookmarks("BM_Fastighetsbeteckning").Range
BM_Fastighetsbeteckning.Text = Me.TextBox1.Value
ThisDocument.Bookmarks.Add "BM_Fastighetsbeteckning", BM_Fastighetsbeteckning
End If

It works and is does not try to write if the bookmark is missing (i have many other textboxes and hundreds of bookmarks). This is used to generate the document but the problem is when there is no value in the textbox. Then it removes the text from the bookmark (since there is no text in the textbox). I also use this to revise already generated documents and i don´t want the existing data in the document to be deleted.
How do i make it so that it only use the textbox if i have written something in the textbox?
I tried this but it does nothing:

If Me.TextBox1.Value = True Then
If ThisDocument.Bookmarks.Exists("BM_Fastighetsbeteckning") = True Then
Dim BM_Fastighetsbeteckning As Range
Set BM_Fastighetsbeteckning = ThisDocument.Bookmarks("BM_Fastighetsbeteckning").Range
BM_Fastighetsbeteckning.Text = Me.TextBox1.Value
ThisDocument.Bookmarks.Add "BM_Fastighetsbeteckning", BM_Fastighetsbeteckning
End If
End If

What am i doing wrong?

You might try:

If Not TextBox1 = vbNullString Then

End If

Thanks, Greg, that did the trick :clap:

This is the finshed code:

Code:

---

If Not TextBox1 = vbNullString Then
    If ThisDocument.Bookmarks.Exists("BM_Fastighetsbeteckning") = True Then
    Dim BM_Fastighetsbeteckning As Range
    Set BM_Fastighetsbeteckning = ThisDocument.Bookmarks("BM_Fastighetsbeteckning").Range
    BM_Fastighetsbeteckning.Text = Me.TextBox1.Value
    ThisDocument.Bookmarks.Add "BM_Fastighetsbeteckning", BM_Fastighetsbeteckning
    End If
    End If

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