SumProduct result as Text Box value in VBA

[FBZM_27]

Hi everyone,
I'm new to this forum and this is my first post.
I have a worksheet where I use this function =SUMPRODUCT(--(MONTH('2014'!C1:XFD1)=MONTH(C1)),--(YEAR('2014'!C1:XFD1)=YEAR(C1))+0,'2014'!C25:XFD25) to calculate the total sales volume in a given month and year.
I want the result of this function to show in a text box of a user form I'm creating but I don't know how.
I tried a lot of solutions I read here on Mr.Excel but I don't really know what I'm doing most of the time so I didn't make any progress.
Could you help me?

 

[FBZM_27]

I kept trying yesterday and this works partially:

Dim P As Integer
P = Evaluate("=SUMPRODUCT(--(Month(C1:XFD1)=Month(C1)),--(Year(C1:XFD1)=Year(C1))+0,C25:XFD25)")
txtParziale = P

I said it works partially because the result I get in the text box is not the sum of all values in the cells in range C25:XFD25, if the corresponding cell in range C1:XFD1 meets my month and year criteria, but only the value in the first cell of the range, which is C25.
The criteria seem to be working fine so I believe I'm not handling ranges properly.
Could someone help me?

 

[FBZM_27]

I kept trying today as well and now I'm pretty sure the problem isn't how I'm handling ranges but the format of dates in C1:XFD1.
I believe they're seen as text, not as numbers, but I'll try to figure out more tomorrow.

 

[FBZM_27]

As you may guess, oh imaginary readers, I kept trying and finallly got it right.
The problem was that dates in range C1:XFD1 weren't set as dates (you can see if a date is a date by checking if you get the it's serial number when formatting the cell as number).
To solve it I simply had to convert any input to date before putting it in a cell:
Range("C1").Value = CDate(txtData.Value)
instead of
Range("C1").Value = txtData.Value
I guess excel helps those who help themselves.