Validate Excel(Spreadsheet) File Using EPPlus

Question

Scenario: have an excel sheet which contains user data. Need to validate the excel sheet before inserting(if new) or updating(if existing) any user data in the database. If any cell has incorrect data or empty data, that cell will be highlighted with red and has a comment explaining the error.
eg: email is not in correct format

Answer 1

I thought of posting this as a solution, so that this will help to anyone having trouble validating excel sheet using EPPlus.
EPPlus version: 4.5.2.1

Following is the excel sheet structure.

Following is the full code to validate the excel sheet.

    [HttpPost]
    public ActionResult BulkUserUpload(HttpPostedFileBase uploadFile)
    {
        string          tempFileName            = string.Empty;
        string          errorMessage            = string.Empty;

        if (uploadFile != null && uploadFile.ContentLength > 0)
        {
            //ExcelExtension contains array of excel extension types
            if ( Config.ExcelExtension.Any(p => p.Trim() == Path.GetExtension(uploadFile.FileName)) )
            {
                //save the uploaded excel file to temp location
                SaveExcelTemp(uploadFile, out tempFileName);
                //validate the excel sheet
                if (ValidateExcel(tempFileName, out errorMessage))
                {
                    //save the data
                    SaveExcelDataToDatabase(tempFileName);
                    //spreadsheet is valid, show success message or any logic here
                }
                else
                {
                    //set error message to shown in front end
                    ViewBag.ErrorMessage        = errorMessage;
                }
            }
            else
            {
                //excel sheet is not uploaded, show error message
            }                                
        }
        else
        {
            //file is not uploaded, show error message
        }

        return View();
    }


    private bool ValidateExcel(string tempFileName, out string errorMessage)
    {
        bool                result              = true;
        string              error               = string.Empty;
        string              filePath            = GetTempFilePath(tempFileName);
        FileInfo            fileInfo            = new FileInfo(filePath);
        ExcelPackage        excelPackage        = new ExcelPackage(fileInfo);
        ExcelWorksheet      worksheet           = excelPackage.Workbook.Worksheets.First();
        int                 totalRows           = worksheet.Dimension == null ? -1 : worksheet.Dimension.End.Row; //worksheet total rows
        int                 totalCols           = worksheet.Dimension == null ? -1 : worksheet.Dimension.End.Column; // total columns

        //check spread sheet has rows (empty spreadsheet uploaded)
        if (totalRows == -1)
        {
            result                              = false;
            error                               = "Empty spread sheet uploaded.";
        }
        //check rows are more than or equal 2 (spread sheet has only header row)
        else if (totalRows < 2)
        {
            result                              = false;
            error                               = "Spread sheet does not contain any data";
        }
        //check total columns equal to headers defined (less columns)
        else if (totalCols > 0 && totalCols != GetColumnHeaders().Count)
        {
            result                              = false;
            error                               = "Spread sheet column header value mismatch.";
        }

        if (result)
        {
            //validate header columns
            result                              &= ValidateColumns(worksheet, totalCols);

            if (result)
            {
                //validate data rows, skip the header row (data rows start from 2)
                result                          &= ValidateRows(worksheet, totalRows, totalCols);
            }

            if (!result)
            {
                error                           = "There are some errors in the uploaded file. Please correct them and upload again.";
            }
        }

        errorMessage                            = error;
        worksheet.Cells[worksheet.Dimension.Address].AutoFitColumns();
        excelPackage.Save();

        return result;
    }

Following are the validation methods

    private bool SetError(ExcelRange cell, string errorComment)
    {           
        var         fill        = cell.Style.Fill;
        fill.PatternType        = OfficeOpenXml.Style.ExcelFillStyle.Solid;
        fill.BackgroundColor.SetColor(System.Drawing.Color.Red);
        cell.AddComment(errorComment, "");

        return false;
    }

    private bool ValidateHeaderColumns(ExcelWorksheet worksheet, int totlaColumns)
    {
        bool                result                  = true;
        List<string>        listColumnHeaders       = GetColumnHeaders();

        for (int i = 1; i < totlaColumns; i++)
        {
            var             cell                    = worksheet.Cells[1, i]; //header columns are in first row

            if (cell.Value != null)
            {
                //column header has a value
                if (!listColumnHeaders.Contains(cell.Value.ToString()))
                {
                    result                          &= SetError(cell, "Invalid header. Please correct.");
                }
            }
            else
            {
                //empty header
                result                              &= SetError(cell, "Empty header. Remove the column.");
            }
        }

        return result;
    }

    private bool ValidateRows(ExcelWorksheet worksheet, int totalRows, int totalCols)
    {
        bool        result              = true;

        for (int i = 2; i <= totalRows; i++) //data rows start from 2`
        {
            for (int j = 1; j <= totalCols; j++)
            {
                var         cell        = worksheet.Cells[i, j];

                switch (j)
                {
                    //email address
                    case 1:
                        {
                            result      &= ValidateEmailAddress(cell, "Email address");
                            break;
                        }
                    //first name
                    case 2:
                        {
                            result      &= ValidateText(cell, "First name");
                            break;
                        }
                    //last name
                    case 3:
                        {
                            result      &= ValidateText(cell, "Last name");
                            break;
                        }
                    //address line 1
                    case 4:
                        {
                            result      &= ValidateText(cell, "Address line 1");
                            break;
                        }
                    //address line 2
                    case 5:
                        {
                            result      &= ValidateText(cell, "Address line 2");
                            break;
                        }
                    //city
                    case 6:
                        {
                            result      &= ValidateText(cell, "City");
                            break;
                        }
                    //telephone number
                    case 7:
                        {
                            result      &= ValidateText(cell, "Telephone number");
                            break;
                        }
                    //mobile number
                    case 8:
                        {
                            result      &= ValidateText(cell, "Mobile number");
                            break;
                        }
                    //job title
                    case 9:
                        {
                            result      &= ValidateJobTitle(cell, "Job title");
                            break;
                        }
                    //salary
                    case 10:
                        {
                            result      &= ValidateNumber(cell, "Salary");
                            break;
                        }
                    //role
                    case 11:
                        {
                            result      &= ValidateRole(cell, "Role");
                            break;
                        }
                    //branch
                    case 12:
                        {
                            result      &= ValidateBranch(cell, "Branch");
                            break;
                        }
                    //joined date
                    case 13:
                        {
                            result      &= ValidateDate(cell, "Joined date");
                            break;
                        }
                }                   
            }
        }

        return result;
    }

    private bool ValidateEmailAddress(ExcelRange cell, string columnName)
    {
        bool        result      = true;
        result                  = ValidateText(cell, columnName); //validate if empty or not

        if (result)
        {
            if (!ValidateEmail(cell.Value.ToString())) //ValidateEmail => true, if email format is correct
            {
                result          = SetError(cell, "Email address format is invalid.");
            }
            else if (cell.Value.ToString().Length > 150)
            {
                result          = SetError(cell, "Email address too long. Max characters 150.");
            }
        }

        return result;
    }

    private bool ValidateText(ExcelRange cell, string columnName)
    {
        bool        result      = true;
        string      error       = string.Format("{0} is empty", columnName);

        if (cell.Value != null)
        {
            //check if cell value has a value
            if (string.IsNullOrWhiteSpace(cell.Value.ToString()))
            {
                result          = SetError(cell, error);
            }
        }
        else
        {
            result              = SetError(cell, error);
        }

        return result;
    }


    private bool ValidateNumber(ExcelRange cell, string columnName)
    {
        bool        result      = true;
        double      value       = 0.0;
        string      error       = string.Format("{0} format is incorrect.", columnName);
        result                  = ValidateText(cell, columnName);

        if (result)
        {
            if (!double.TryParse(cell.Value.ToString(), out value))
            {
                result          = SetError(cell, error);
            }
        }

        return result;
    }

    private bool ValidateDate(ExcelRange cell, string columnName)
    {
        bool            result      = true;
        DateTime        date        = DateTime.MinValue;
        string          error       = string.Format("{0} format is incorrect.", columnName);
        result                      = ValidateText(cell, columnName);

        if (result)
        {
            if (!DateTime.TryParse(cell.Value.ToString(), out date))
            {
                result              = SetError(cell, error);
            }
        }

        return result;
    }

    private bool ValidateJobTitle(ExcelRange cell, string columnName)
    {
        bool                result              = true;
        string              error               = "Job title does not exist.";
        List<JobTitle>      listJobTitle        = JobTitle.GetJobTitles((int)JobTitle.JobTitleStatus.Active);
        result                                  = ValidateText(cell, columnName);

        if (result)
        {
            if (!listJobTitle.Any(x => x.Name.ToLowerInvariant() == cell.Value.ToString().ToLowerInvariant()))
            {
                result                          = SetError(cell, error);
            }
        }

        return result;
    }

Same implementation for the methods ValidateBranch() and ValidateRole() like in the ValidateJobTitle() method.

Following is the validated excel sheet with errors.

Hope this will help to anyone.