VBA - Date Format "mm/dd/yyyy" - vba

Question

My excel file format for date is Mar 30 2016 10:12:27:396AM i want to change the format to mm/dd/yyyy. but i'm having an error on my code..
Run-time error '13': Type mismatch
this is the line i got the error SecondDate = Trim(Sheet2.Range("B" & RowNo).Value)
Note: The data from Column A and B are dates
My Code:
Dim Result, RowNo As Long
Dim FirstDate As Variant
Dim SecondDate As Variant
RowNo = 2
FirstDate = Trim(Sheet2.Range("A" & RowNo).Value)
SecondDate = Trim(Sheet2.Range("B" & RowNo).Value)
FirstDate = Format(FirstDate, "mm/dd/yyyy")
SecondDate = Format(SecondDate, "mm/dd/yyyy")
Do Until Sheet2.Cells(RowNo, 1) = ""
FirstDate = Sheet2.Cells(RowNo, 1)
SecondDate = Sheet2.Cells(RowNo, 2)
If DateDiff("d", FirstDate, SecondDate) >= 15 Then
Sheet2.Cells(RowNo, 3) = "1"
Sheet2.Cells(RowNo, 4) = "2"
End If
RowNo = RowNo + 1
Loop
i do feel like im in the right path..am i missing something?
Update: My script will get the data from Column A and Column B and using the DateDiff function i will subtract both columns if the difference is <15 tag it from Column C and D as 1, 2
note:
i only subtract the days from both columns.. but is it possible to subtract both days and years?
it's working if i use the format mm/dd/yyyy in the excel but if i use other format i got the error mismatch
Updated 2:
Column A | Column B | Column C
Mar 1 2016 10:12:27:396AM | Mar 30 2016 10:12:27:396AM |
Mar 1 2016 10:12:27:396AM | Mar 30 2016 10:12:27:396AM |
in my file this is the date format, if you try this as sample data it won't work maybe because VBA doesnt recognize this as dateformat?

Answer 1

Perhaps this will address what you are trying to do.
Test Input:
Test Output:
Code:
Sub DateStuff()
Dim FirstDate As Range, SecondDate As Range
Dim RowNo As Long
Set FirstDate = Sheet4.Range("A1")
Set SecondDate = Sheet4.Range("A2")
FirstDate.NumberFormat = "mm/dd/yyyy"
SecondDate.NumberFormat = "mm/dd/yyyy"
RowNo = 2
Do Until Sheet4.Cells(RowNo, 1) = ""
Set FirstDate = Sheet4.Cells(RowNo, 1)
Set SecondDate = Sheet4.Cells(RowNo, 2)
If IsDate(FirstDate.Value) And IsDate(SecondDate.Value) Then
If DateDiff("d", FirstDate, SecondDate) >= 15 Then
Sheet4.Cells(RowNo, 3) = 1
Sheet4.Cells(RowNo, 4) = 2
End If
End If
RowNo = RowNo + 1
Loop
End Sub
Please spend a few minutes to understand this code:
FirstDate and SecondDate are Range data types, not Date or Variant. The data in the cells they point to are Date or something else.
When setting the format, it sets how it is displayed on the worksheet. It is not formatting a character string in VBA.
Before making the DateDiff call, ensure both FirstDate and SecondDate really contain Date datatypes in the cells, this will prevent many errors.
Operations on Date datatypes using Date functions are NOT dependent on formatting. They use the internal Date type. Formatting ONLY affects how a date is converted to a string and/or displayed on the worksheets.
You asked about checking year instead of day. There are built in VBA functions (e.g. Year, Month, etc.) that will help with this.
As to your update to your question:
I am not sure where you are getting your time codes from, but Excel does not recognize :000 for milliseconds. It uses .000. See below ...