Get Last non empty column and row index from excel

Question

I am trying to remove all extra blank rows and columns from an excel file using Interop Library.

I followed this question Fastest method to remove Empty rows and Columns From Excel Files using Interop and i find it helpful.

But i have excel files that contains a small set of data but a lot of empty rows and columns (from the last non empty row (or column) to the end of the worksheet)

I tried looping over Rows and Columns but the loop is taking hours.

I am trying to get the last non-empty row and column index so i can delete the whole empty range in one line

XlWks.Range("...").EntireRow.Delete(xlShiftUp)

Note: i am trying to get the last row containing data to remove all extra blanks (after this row , or column)

Any suggestions?

Answer 1

• To get last non empty column/row index the Excel function Find can be used. See GetLastIndexOfNonEmptyCell.
• Then the Excel Worksheet Function CountA is used to determine if the cells are empty and union the entire rows/columns to one rows/columns range.
• This ranges are deleted finally at once.

---

public void Yahfoufi(string excelFile)
{
    var exapp = new Microsoft.Office.Interop.Excel.Application {Visible = true};
    var wrb = exapp.Workbooks.Open(excelFile);
    var sh = wrb.Sheets["Sheet1"];
    var lastRow = GetLastIndexOfNonEmptyCell(exapp, sh, XlSearchOrder.xlByRows);
    var lastCol = GetLastIndexOfNonEmptyCell(exapp, sh, XlSearchOrder.xlByColumns);
    var target = sh.Range[sh.Range["A1"], sh.Cells[lastRow, lastCol]];
    Range deleteRows = GetEmptyRows(exapp, target);
    Range deleteColumns = GetEmptyColumns(exapp, target);
    deleteColumns?.Delete();
    deleteRows?.Delete();
}

private static int GetLastIndexOfNonEmptyCell(
    Microsoft.Office.Interop.Excel.Application app,
    Worksheet sheet,
    XlSearchOrder searchOrder)
{
    Range rng = sheet.Cells.Find(
        What: "*",
        After: sheet.Range["A1"],
        LookIn: XlFindLookIn.xlFormulas,
        LookAt: XlLookAt.xlPart,
        SearchOrder: searchOrder,
        SearchDirection: XlSearchDirection.xlPrevious,
        MatchCase: false);
    if (rng == null)
        return 1;
    return searchOrder == XlSearchOrder.xlByRows
        ? rng.Row
        : rng.Column;
}

private static Range GetEmptyRows(
    Microsoft.Office.Interop.Excel.Application app,
    Range target)
{
    Range result = null;
    foreach (Range r in target.Rows)
    {
        if (app.WorksheetFunction.CountA(r.Cells) >= 1)
            continue;
        result = result == null
            ? r.EntireRow
            : app.Union(result, r.EntireRow);
    }
    return result;
}

private static Range GetEmptyColumns(
    Microsoft.Office.Interop.Excel.Application app,
    Range target)
{
    Range result = null;
    foreach (Range c in target.Columns)
    {
        if (app.WorksheetFunction.CountA(c.Cells) >= 1)
            continue;
        result = result == null
            ? c.EntireColumn
            : app.Union(result, c.EntireColumn);
    }
    return result;
}

The two functions for getting empty ranges of rows/columns could be refactored to one function, something like this:

private static Range GetEntireEmptyRowsOrColumns(
    Microsoft.Office.Interop.Excel.Application app,
    Range target,
    Func<Range, Range> rowsOrColumns,
    Func<Range, Range> entireRowOrColumn)
{
    Range result = null;
    foreach (Range c in rowsOrColumns(target))
    {
        if (app.WorksheetFunction.CountA(c.Cells) >= 1)
            continue;
        result = result == null
            ? entireRowOrColumn(c)
            : app.Union(result, entireRowOrColumn(c));
    }
    return result;
}

And then just call it:

Range deleteColumns = GetEntireEmptyRowsOrColumns(exapp, target, (Func<Range, Range>)(r1 => r1.Columns), (Func<Range, Range>)(r2 => r2.EntireColumn));
Range deleteRows = GetEntireEmptyRowsOrColumns(exapp, target, (Func<Range, Range>)(r1 => r1.Rows), (Func<Range, Range>)(r2 => r2.EntireRow));
deleteColumns?.Delete();
deleteRows?.Delete();

---

Note: for more informations have a look e.g. on this SO question.

Edit

Try to simply clear the content of all the cells which are after the last used cell.

public void Yahfoufi(string excelFile)
{
    var exapp = new Microsoft.Office.Interop.Excel.Application {Visible = true};
    var wrb = exapp.Workbooks.Open(excelFile);
    var sh = wrb.Sheets["Sheet1"];
    var lastRow = GetLastIndexOfNonEmptyCell(exapp, sh, XlSearchOrder.xlByRows);
    var lastCol = GetLastIndexOfNonEmptyCell(exapp, sh, XlSearchOrder.xlByColumns);

    // Clear the columns
    sh.Range(sh.Cells(1, lastCol + 1), sh.Cells(1, Columns.Count)).EntireColumn.Clear();

    // Clear the remaining cells
    sh.Range(sh.Cells(lastRow + 1, 1), sh.Cells(Rows.Count, lastCol)).Clear();

}