Definite. I expected it to work, but it does nothing. Can you try my code on your machine? Here is my code (I saved the form as a class to get it):

oform=CREATEOBJECT('changefont')
oform.show()


DEFINE CLASS changefont AS form


	Top = 0
	Left = 0
	Height = 199
	Width = 425
	DoCreate = .T.
	Caption = "Change Textbox FontName Example"
	Name = "Form1"
	WindowType=1
	DIMENSION gafontarray[1,1]


	ADD OBJECT combo1 AS combobox WITH ;
		RowSourceType = 2, ;
		RowSource = "cafonts.cfont", ;
		ControlSource = "m.cn_preprta", ;
		Height = 24, ;
		Left = 48, ;
		Style = 2, ;
		Top = 24, ;
		Width = 228, ;
		Name = "Combo1"


	ADD OBJECT text1 AS textbox WITH ;
		Value = "This is an example of the font.", ;
		Height = 23, ;
		Left = 48, ;
		ReadOnly = .T., ;
		TabStop = .F., ;
		Top = 58, ;
		Width = 336, ;
		Name = "Text1"


	ADD OBJECT combo2 AS combobox WITH ;
		RowSourceType = 2, ;
		RowSource = "casize.csize", ;
		ControlSource = "m.cn_preprtb", ;
		Height = 24, ;
		Left = 288, ;
		Style = 2, ;
		Top = 24, ;
		Width = 60, ;
		Name = "Combo2"


	PROCEDURE load
		SET SAFETY OFF
		CREATE TABLE cafonts (cfont c(30))
		IF !USED('cafonts')
			USE cafonts IN 0
		ENDIF
		CREATE TABLE casize (csize c(2))
		IF !USED('casize')
			USE casize IN 0
		ENDIF
	ENDPROC
	
	PROCEDURE Init
		*--init
		=AFONT(thisform.gaFontArray)
		SELE cafonts
		FOR i = 1 TO ALEN(thisform.gaFontArray,1)
			APPEND BLANK
			REPLACE cafonts.cfont WITH gaFontArray(i)
		ENDFOR
		GO TOP
		SELE casize
		FOR i = 6 TO 12 STEP 2
			APPEND BLANK
			REPLACE casize.csize WITH ALLTRIM(STR(i))
		ENDFOR
		GO TOP
		LOCATE FOR casize.csize="12"
		IF EOF()
			GO TOP
		ENDIF
		m.cn_preprtb=casize.csize
		SELE cafonts
		INDEX ON cfont TAG cfont
		SET ORDER TO TAG cfont
		GO TOP
		m.cn_preprta=cafonts.cfont
		thisform.combo2.requery()
		thisform.combo2.refresh()
		thisform.text1.click()
		DODEFAULT()
	ENDPROC


	PROCEDURE combo1.Valid
		*!*	THISFORM.text1.fontname=thisform.combo1.value
		*!*	THISFORM.text1.value="This is an example of the font "+thisform.combo1.value
		*!*	THISFORM.text1.fontsize=11
		*!*	THISFORM.text1.refresh()
		DODEFAULT()
		THISFORM.text1.click()
	ENDPROC


	PROCEDURE text1.Click
		THIS.value="This is an example of the font "+thisform.combo1.value
		This.fontname=thisform.combo1.value
		thisform.refresh()
		DODEFAULT()
	ENDPROC


ENDDEFINE

Tracy
>>I've been trying to change the fontname of a textbox programmatically using the following code:
>>
>>

>>THIS.value="This is an example of the font "+thisform.combo1.value
>>This.fontname=thisform.combo1.value
>>this.refresh()
>>

>>
>>However, while the value changes as it should, the fontname does not. The textbox retains the original fontname from when the form was instantiated. Any ideas?
>
>Are you sure? I put your code in a textbox click() method and it works just as you would expect...