[excel] Iterating through populated rows

So I am trying to iterate through a worksheet in an Excel spreadsheet using VBA. I want to iterate through each row, and then through each column, and despite googling, I can't actually find an intuitive way to do this.

I'm assuming that the first cell of a row must be populated, if its not, then that must be the end. I can enforce this

My current approach is to iterate through the rows, then try and get the value of the first cell, but I can't figure it out. I've come across some questions here and elsewhere that use ranges and such, but nothing that helps me write code.

The current approach is:

Set sh = ActiveSheet
RowCount = 0
For Each rw In sh.Rows
    'If Row.Cells(1, 1).Value = "" Then Exit For
    RowCount = RowCount + 1
Next rw
MsgBox (RowCount)

Now when I run this, I get some huge number, which is wrong as the table only has about 25 rows. I commented the first line out as it wasn't working.

What can I change in the first line in the For Loop to correctly break when it finds a row where the first cell is empty?

I'm going to make a couple of assumptions in my answer. I'm assuming your data starts in A1 and there are no empty cells in the first column of each row that has data.

This code will:

1. Find the last row in column A that has data
2. Loop through each row
3. Find the last column in current row with data
4. Loop through each cell in current row up to last column found.

This is not a fast method but will iterate through each one individually as you suggested is your intention.

Sub iterateThroughAll()
    ScreenUpdating = False
    Dim wks As Worksheet
    Set wks = ActiveSheet

    Dim rowRange As Range
    Dim colRange As Range

    Dim LastCol As Long
    Dim LastRow As Long
    LastRow = wks.Cells(wks.Rows.Count, "A").End(xlUp).Row

    Set rowRange = wks.Range("A1:A" & LastRow)

    'Loop through each row
    For Each rrow In rowRange
        'Find Last column in current row
        LastCol = wks.Cells(rrow, wks.Columns.Count).End(xlToLeft).Column
        Set colRange = wks.Range(wks.Cells(rrow, 1), wks.Cells(rrow, LastCol))

        'Loop through all cells in row up to last col
        For Each cell In colRange
            'Do something to each cell
            Debug.Print (cell.Value)
        Next cell
    Next rrow
    ScreenUpdating = True
End Sub

For the benefit of anyone searching for similar, see worksheet .UsedRange,
e.g. ? ActiveSheet.UsedRange.Rows.Count
and loops such as
For Each loopRow in Sheets(1).UsedRange.Rows: Print loopRow.Row: Next