i would like to iterate my controls and if its a textbox check a value

i have :

Dim txt As Control

For Each txt In Me.Controls
If txt Is TextBox Then <-- wrong, how can i check?

If txt.Tag = "r" Then

If Len(Trim(txt.Text)) = 0 Then
txt.Text = "Required Field"
txt.Interior.Color = vbYellow
bRequired = False
End If
End If
End If
Next

There are 2 ways.