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EPPLUS: Length of a DataValidation list cannot exceed 255 characters

This question is answered on a basic level on another post: here However for my case I am not able to hard code the validation values into the sheet I am pulling them from a database based on the content of the cell and will need to do a separate validation for 4 columns on every row. Is there a way this can be achieved? Thank you in advance.
// Data Validations //
// Product Validation //
for (int i = 2; i < rowCount; i++)
{
var val = ws.DataValidations.AddListValidation(ws.Cells[i, 5].Address);
val.ShowErrorMessage = true;
val.ErrorTitle = "Entry was invalid.";
val.Error = "Please choose options from the drop down only.";
var ticketEntity = ticketQueryable.Where(o => o.TTSTicketNumber == ws.Cells[i, 3].Value.ToString()).Single<CustCurrentTicketEntity>();
var prodIds = prodExtQueryable.Where(p => p.ZoneId == ticketEntity.ZoneId && p.TicketTypeId == ticketEntity.TicketTypeId);
if (ticketEntity != null)
{
var prodIdsList = new List<int>();
foreach (var prodId in prodIds)
{
prodIdsList.Add(prodId.ProductId);
}
var ProductList = ProductCache.Instance.AllProducts.Where(p => prodIdsList.Contains(p.ProductId)).Select(p => new SelectListItem() { Value = p.ProductId.ToString(), Text = p.Name });
foreach (var Result in ProductList)
{
var product = Result.Text;
val.Formula.Values.Add(product);
}
}
}

So yes as Ernie said What I did was add a second sheet "ProductValidations" and set it to Hidden (unhide it to check that it is working). I then Load my data from the DataTable and then add some basic EPPLUS formatting. I then iterate over the Rows and Insert values into the "ProductValidations" sheet for each cell. Next I convert my column number to the correct Excel Column letter name (A, AC, BCE etc) I then create a string to pass back as an Excel formula targeting the correct range of cells in the "ProductValidations" sheet. Also to anyone having an issue downloading the Excel file from the server this guid method works just fine for me.
public ActionResult DownloadExcel(EntityReportModel erModel, string filename)
{
var dataResponse = iEntityViewService.LoadEntityView(new EntityViewInput
{
SecurityContext = SessionCache.Instance.SecurityContext,
EntityViewName = "Ticket",
Parameters = new Dictionary<string, object> {
{"MinTicketDateTime", "04/26/16"}
}
});
var table = dataResponse.DataSet.Tables[0];
filename = "TICKETS-" + DateTime.Now.ToString("yyyy-MM-dd--hh-mm-ss") + ".xlsx";
using (ExcelPackage pack = new ExcelPackage())
{
ExcelWorksheet ws = pack.Workbook.Worksheets.Add(filename);
//Add second sheet to put Validations into
ExcelWorksheet productVal = pack.Workbook.Worksheets.Add("ProductValidations");
// Hide Validation Sheet
productVal.Hidden = OfficeOpenXml.eWorkSheetHidden.Hidden;
// Load the data from the datatable
ws.Cells["A1"].LoadFromDataTable(table, true);
ws.Cells[ws.Dimension.Address].AutoFitColumns();
int columnCount = table.Columns.Count;
int rowCount = table.Rows.Count;
// Format Worksheet//
ws.Row(1).Style.Font.Bold = true;
List<string> deleteColumns = new List<string>() {
"CurrentTicketId",
};
List<string> dateColumns = new List<string>() {
"TicketDateTime",
"Updated",
"InvoiceDate"
};
ExcelRange r;
// Format Dates
for (int i = 1; i <= columnCount; i++)
{
// if cell header value matches a date column
if (dateColumns.Contains(ws.Cells[1, i].Value.ToString()))
{
r = ws.Cells[2, i, rowCount + 1, i];
r.AutoFitColumns();
r.Style.Numberformat.Format = #"mm/dd/yyyy hh:mm";
}
}
// Delete Columns
for (int i = 1; i <= columnCount; i++)
{
// if cell header value matches a delete column
if ((ws.Cells[1, i].Value != null) && deleteColumns.Contains(ws.Cells[1, i].Value.ToString()))
{
ws.DeleteColumn(i);
}
}
int col = 0;
int Prow = 0;
int valRow = 1;
// Data Validations //
// Iterate over the Rows and insert Validations
for (int i = 2; i-2 < rowCount; i++)
{
Prow = 0;
col++;
valRow++;
// Add Validations At this row in column 7 //
var ProdVal = ws.DataValidations.AddListValidation(ws.Cells[valRow, 7].Address);
ProdVal.ShowErrorMessage = true;
ProdVal.ErrorTitle = "Entry was invalid.";
ProdVal.Error = "Please choose options from the drop down only.";
var ticketEntity = ticketQueryable.Where(o => o.TTSTicketNumber == ws.Cells[i, 3].Value.ToString()).Single<CustCurrentTicketEntity>();
// Product Validation //
var prodIds = prodExtQueryable.Where(p => p.ZoneId == ticketEntity.ZoneId && p.TicketTypeId == ticketEntity.TicketTypeId);
if (ticketEntity != null)
{
var prodIdsList = new List<int>();
foreach (var prodId in prodIds)
{
prodIdsList.Add(prodId.ProductId);
}
var ProductList = ProductCache.Instance.AllProducts.Where(p => prodIdsList.Contains(p.ProductId)).Select(p => new SelectListItem() { Value = p.ProductId.ToString(), Text = p.Name });
//For Each Item in the list move the row forward and add that value to the Validation Sheet
foreach (var Result in ProductList)
{
Prow++;
var product = Result.Text;
productVal.Cells[Prow, col].Value = product;
}
// convert column name from a number to the Excel Letters i.e A, AC, BCE//
int dividend = col;
string columnName = String.Empty;
int modulo;
while (dividend > 0)
{
modulo = (dividend - 1) % 26;
columnName = Convert.ToChar(65 + modulo).ToString() + columnName;
dividend = (int)((dividend - modulo) / 26);
}
// Pass back to sheeet as an Excel Formula to get around the 255 Char limit for Validations//
string productValidationExcelFormula = "ProductValidations!" + columnName + "1:" + columnName + Prow;
ProdVal.Formula.ExcelFormula = productValidationExcelFormula;
}
}
// Save File //
var fileStream = new MemoryStream(pack.GetAsByteArray());
string handle = Guid.NewGuid().ToString();
fileStream.Position = 0;
TempData[handle] = fileStream.ToArray();
// Note we are returning a filename as well as the handle
return new JsonResult()
{
Data = new { FileGuid = handle, FileName = filename }
};
}
}
[HttpGet]
public virtual ActionResult Download(string fileGuid, string fileName)
{
if (TempData[fileGuid] != null)
{
byte[] data = TempData[fileGuid] as byte[];
return File(data, "application/vnd.ms-excel", fileName);
}
else
{
//Log err
return new EmptyResult();
}
}

EPPlus - Read Excel Table

Using EPPlus, I want to read an excel table, then store all the contents from each column into its corresponding List. I want it to recognize the table's heading and categorize the contents based on that.
For example, if my excel table is as below:
Id Name Gender
1 John Male
2 Maria Female
3 Daniel Unknown
I want the data to store in List<ExcelData> where
public class ExcelData
{
public string Id { get; set; }
public string Name { get; set; }
public string Gender { get; set; }
}
So that I can call out the contents using the heading name. For example, when I do this:
foreach (var data in ThatList)
{
Console.WriteLine(data.Id + data.Name + data.Gender);
}
It will give me this output:
1JohnMale
2MariaFemale
3DanielUnknown
This is really all I got:
var package = new ExcelPackage(new FileInfo(#"C:\ExcelFile.xlsx"));
ExcelWorksheet sheet = package.Workbook.Worksheets[1];
var table = sheet.Tables.First();
table.Columns.Something //I guess I can use this to do what I want
Please help :(
I have spent long hours searching for sample code regarding this so that I can learn from it but to no avail. I also understand ExcelToLinQ is managed to do that but it can't recognize table.

Not sure why but none of the above solution work for me.
So sharing what worked:
public void readXLS(string FilePath)
{
FileInfo existingFile = new FileInfo(FilePath);
using (ExcelPackage package = new ExcelPackage(existingFile))
{
//get the first worksheet in the workbook
ExcelWorksheet worksheet = package.Workbook.Worksheets[1];
int colCount = worksheet.Dimension.End.Column; //get Column Count
int rowCount = worksheet.Dimension.End.Row; //get row count
for (int row = 1; row <= rowCount; row++)
{
for (int col = 1; col <= colCount; col++)
{
Console.WriteLine(" Row:" + row + " column:" + col + " Value:" + worksheet.Cells[row, col].Value?.ToString().Trim());
}
}
}
}

There is no native but what if you use what I put in this post:
How to parse excel rows back to types using EPPlus
If you want to point it at a table only it will need to be modified. Something like this should do it:
public static IEnumerable<T> ConvertTableToObjects<T>(this ExcelTable table) where T : new()
{
//DateTime Conversion
var convertDateTime = new Func<double, DateTime>(excelDate =>
{
if (excelDate < 1)
throw new ArgumentException("Excel dates cannot be smaller than 0.");
var dateOfReference = new DateTime(1900, 1, 1);
if (excelDate > 60d)
excelDate = excelDate - 2;
else
excelDate = excelDate - 1;
return dateOfReference.AddDays(excelDate);
});
//Get the properties of T
var tprops = (new T())
.GetType()
.GetProperties()
.ToList();
//Get the cells based on the table address
var start = table.Address.Start;
var end = table.Address.End;
var cells = new List<ExcelRangeBase>();
//Have to use for loops insteadof worksheet.Cells to protect against empties
for (var r = start.Row; r <= end.Row; r++)
for (var c = start.Column; c <= end.Column; c++)
cells.Add(table.WorkSheet.Cells[r, c]);
var groups = cells
.GroupBy(cell => cell.Start.Row)
.ToList();
//Assume the second row represents column data types (big assumption!)
var types = groups
.Skip(1)
.First()
.Select(rcell => rcell.Value.GetType())
.ToList();
//Assume first row has the column names
var colnames = groups
.First()
.Select((hcell, idx) => new { Name = hcell.Value.ToString(), index = idx })
.Where(o => tprops.Select(p => p.Name).Contains(o.Name))
.ToList();
//Everything after the header is data
var rowvalues = groups
.Skip(1) //Exclude header
.Select(cg => cg.Select(c => c.Value).ToList());
//Create the collection container
var collection = rowvalues
.Select(row =>
{
var tnew = new T();
colnames.ForEach(colname =>
{
//This is the real wrinkle to using reflection - Excel stores all numbers as double including int
var val = row[colname.index];
var type = types[colname.index];
var prop = tprops.First(p => p.Name == colname.Name);
//If it is numeric it is a double since that is how excel stores all numbers
if (type == typeof(double))
{
if (!string.IsNullOrWhiteSpace(val?.ToString()))
{
//Unbox it
var unboxedVal = (double)val;
//FAR FROM A COMPLETE LIST!!!
if (prop.PropertyType == typeof(Int32))
prop.SetValue(tnew, (int)unboxedVal);
else if (prop.PropertyType == typeof(double))
prop.SetValue(tnew, unboxedVal);
else if (prop.PropertyType == typeof(DateTime))
prop.SetValue(tnew, convertDateTime(unboxedVal));
else
throw new NotImplementedException(String.Format("Type '{0}' not implemented yet!", prop.PropertyType.Name));
}
}
else
{
//Its a string
prop.SetValue(tnew, val);
}
});
return tnew;
});
//Send it back
return collection;
}
Here is a test method:
[TestMethod]
public void Table_To_Object_Test()
{
//Create a test file
var fi = new FileInfo(#"c:\temp\Table_To_Object.xlsx");
using (var package = new ExcelPackage(fi))
{
var workbook = package.Workbook;
var worksheet = workbook.Worksheets.First();
var ThatList = worksheet.Tables.First().ConvertTableToObjects<ExcelData>();
foreach (var data in ThatList)
{
Console.WriteLine(data.Id + data.Name + data.Gender);
}
package.Save();
}
}
Gave this in the console:
1JohnMale
2MariaFemale
3DanielUnknown
Just be careful if you Id field is an number or string in excel since the class is expecting a string.

This is my working version. Note that the resolvers code is not shown but are a spin on my implementation which allows columns to be resolved even though they are named slightly differently in each worksheet.
public static IEnumerable<T> ToArray<T>(this ExcelWorksheet worksheet, List<PropertyNameResolver> resolvers) where T : new()
{
// List of all the column names
var header = worksheet.Cells.GroupBy(cell => cell.Start.Row).First();
// Get the properties from the type your are populating
var properties = typeof(T).GetProperties().ToList();
var start = worksheet.Dimension.Start;
var end = worksheet.Dimension.End;
// Resulting list
var list = new List<T>();
// Iterate the rows starting at row 2 (ie start.Row + 1)
for (int row = start.Row + 1; row <= end.Row; row++)
{
var instance = new T();
for (int col = start.Column; col <= end.Column; col++)
{
object value = worksheet.Cells[row, col].Text;
// Get the column name zero based (ie col -1)
var column = (string)header.Skip(col - 1).First().Value;
// Gets the corresponding property to set
var property = properties.Property(resolvers, column);
try
{
var propertyName = property.PropertyType.IsGenericType
? property.PropertyType.GetGenericArguments().First().FullName
: property.PropertyType.FullName;
// Implement setter code as needed.
switch (propertyName)
{
case "System.String":
property.SetValue(instance, Convert.ToString(value));
break;
case "System.Int32":
property.SetValue(instance, Convert.ToInt32(value));
break;
case "System.DateTime":
if (DateTime.TryParse((string) value, out var date))
{
property.SetValue(instance, date);
}
property.SetValue(instance, FromExcelSerialDate(Convert.ToInt32(value)));
break;
case "System.Boolean":
property.SetValue(instance, (int)value == 1);
break;
}
}
catch (Exception e)
{
// instance property is empty because there was a problem.
}
}
list.Add(instance);
}
return list;
}
// Utility function taken from the above post's inline function.
public static DateTime FromExcelSerialDate(int excelDate)
{
if (excelDate < 1)
throw new ArgumentException("Excel dates cannot be smaller than 0.");
var dateOfReference = new DateTime(1900, 1, 1);
if (excelDate > 60d)
excelDate = excelDate - 2;
else
excelDate = excelDate - 1;
return dateOfReference.AddDays(excelDate);
}

Below code will read excel data into a datatable, which is converted to list of datarows.
if (FileUpload1.HasFile)
{
if (Path.GetExtension(FileUpload1.FileName) == ".xlsx")
{
Stream fs = FileUpload1.FileContent;
ExcelPackage package = new ExcelPackage(fs);
DataTable dt = new DataTable();
dt= package.ToDataTable();
List<DataRow> listOfRows = new List<DataRow>();
listOfRows = dt.AsEnumerable().ToList();
}
}
using OfficeOpenXml;
using System.Data;
using System.Linq;
public static class ExcelPackageExtensions
{
public static DataTable ToDataTable(this ExcelPackage package)
{
ExcelWorksheet workSheet = package.Workbook.Worksheets.First();
DataTable table = new DataTable();
foreach (var firstRowCell in workSheet.Cells[1, 1, 1, workSheet.Dimension.End.Column])
{
table.Columns.Add(firstRowCell.Text);
}
for (var rowNumber = 2; rowNumber <= workSheet.Dimension.End.Row; rowNumber++)
{
var row = workSheet.Cells[rowNumber, 1, rowNumber, workSheet.Dimension.End.Column];
var newRow = table.NewRow();
foreach (var cell in row)
{
newRow[cell.Start.Column - 1] = cell.Text;
}
table.Rows.Add(newRow);
}
return table;
}
}

Yet another way to do it.
I used Ernie S solution but it didn't work if I had empty cells in the first data row (it wasn't able to guess the data type from it).
So instead of getting a data type from Excel table I get it from the T parameter class properties using reflection.
/// <summary>
/// Converts table to list of T objects
/// </summary>
/// <typeparam name="T">The type to return</typeparam>
/// <param name="table">Data source</param>
/// <returns>List of T objects</returns>
public static IEnumerable<T> ConvertToObjects<T>(this ExcelTable table) where T : new()
{
ExcelCellAddress start = table.Address.Start;
ExcelCellAddress end = table.Address.End;
List<ExcelRange> cells = new();
for (int r = start.Row; r <= end.Row; r++)
for (int c = start.Column; c <= end.Column; c++)
cells.Add(table.WorkSheet.Cells[r, c]);
List<IGrouping<int, ExcelRange>> allRows = cells
.GroupBy(cell => cell.Start.Row)
.OrderBy(cell => cell.Key)
.ToList();
IEnumerable<PropertyInfo> typeProperties = typeof(T).GetProperties();
IGrouping<int, ExcelRangeBase> header = allRows.First();
Dictionary<PropertyInfo, int> columns = new();
foreach (ExcelRangeBase col in header)
{
string propName = col.GetValue<string>();
PropertyInfo propInfo = typeProperties.FirstOrDefault(x => x.Name.Equals(propName));
if (propInfo != null)
{
columns.Add(propInfo, col.Start.Column);
}
}
IEnumerable<IGrouping<int, ExcelRangeBase>> rows = allRows.Skip(1);
List<T> objects = new();
foreach (IGrouping<int, ExcelRangeBase> row in rows)
{
T obj = new();
foreach (KeyValuePair<PropertyInfo, int> colInfo in columns)
{
ExcelRangeBase col = row.First(x => x.Start.Column == colInfo.Value);
if (col.Value == null)
continue;
object value = Convert.ChangeType(col.Value, Nullable.GetUnderlyingType(colInfo.Key.PropertyType) ?? colInfo.Key.PropertyType);
colInfo.Key.SetValue(obj, value);
}
objects.Add(obj);
}
return objects;
}

I have got an error on the first answer so I have changed some code line.
Please try my new code, it's working for me.
using OfficeOpenXml;
using OfficeOpenXml.Table;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
public static class ImportExcelReader
{
public static List<T> ImportExcelToList<T>(this ExcelWorksheet worksheet) where T : new()
{
//DateTime Conversion
Func<double, DateTime> convertDateTime = new Func<double, DateTime>(excelDate =>
{
if (excelDate < 1)
{
throw new ArgumentException("Excel dates cannot be smaller than 0.");
}
DateTime dateOfReference = new DateTime(1900, 1, 1);
if (excelDate > 60d)
{
excelDate = excelDate - 2;
}
else
{
excelDate = excelDate - 1;
}
return dateOfReference.AddDays(excelDate);
});
ExcelTable table = null;
if (worksheet.Tables.Any())
{
table = worksheet.Tables.FirstOrDefault();
}
else
{
table = worksheet.Tables.Add(worksheet.Dimension, "tbl" + ShortGuid.NewGuid().ToString());
ExcelAddressBase newaddy = new ExcelAddressBase(table.Address.Start.Row, table.Address.Start.Column, table.Address.End.Row + 1, table.Address.End.Column);
//Edit the raw XML by searching for all references to the old address
table.TableXml.InnerXml = table.TableXml.InnerXml.Replace(table.Address.ToString(), newaddy.ToString());
}
//Get the cells based on the table address
List<IGrouping<int, ExcelRangeBase>> groups = table.WorkSheet.Cells[table.Address.Start.Row, table.Address.Start.Column, table.Address.End.Row, table.Address.End.Column]
.GroupBy(cell => cell.Start.Row)
.ToList();
//Assume the second row represents column data types (big assumption!)
List<Type> types = groups.Skip(1).FirstOrDefault().Select(rcell => rcell.Value.GetType()).ToList();
//Get the properties of T
List<PropertyInfo> modelProperties = new T().GetType().GetProperties().ToList();
//Assume first row has the column names
var colnames = groups.FirstOrDefault()
.Select((hcell, idx) => new
{
Name = hcell.Value.ToString(),
index = idx
})
.Where(o => modelProperties.Select(p => p.Name).Contains(o.Name))
.ToList();
//Everything after the header is data
List<List<object>> rowvalues = groups
.Skip(1) //Exclude header
.Select(cg => cg.Select(c => c.Value).ToList()).ToList();
//Create the collection container
List<T> collection = new List<T>();
foreach (List<object> row in rowvalues)
{
T tnew = new T();
foreach (var colname in colnames)
{
//This is the real wrinkle to using reflection - Excel stores all numbers as double including int
object val = row[colname.index];
Type type = types[colname.index];
PropertyInfo prop = modelProperties.FirstOrDefault(p => p.Name == colname.Name);
//If it is numeric it is a double since that is how excel stores all numbers
if (type == typeof(double))
{
//Unbox it
double unboxedVal = (double)val;
//FAR FROM A COMPLETE LIST!!!
if (prop.PropertyType == typeof(int))
{
prop.SetValue(tnew, (int)unboxedVal);
}
else if (prop.PropertyType == typeof(double))
{
prop.SetValue(tnew, unboxedVal);
}
else if (prop.PropertyType == typeof(DateTime))
{
prop.SetValue(tnew, convertDateTime(unboxedVal));
}
else if (prop.PropertyType == typeof(string))
{
prop.SetValue(tnew, val.ToString());
}
else
{
throw new NotImplementedException(string.Format("Type '{0}' not implemented yet!", prop.PropertyType.Name));
}
}
else
{
//Its a string
prop.SetValue(tnew, val);
}
}
collection.Add(tnew);
}
return collection;
}
}
How to call this function? please view below code;
private List<FundraiserStudentListModel> GetStudentsFromExcel(HttpPostedFileBase file)
{
List<FundraiserStudentListModel> list = new List<FundraiserStudentListModel>();
if (file != null)
{
try
{
using (ExcelPackage package = new ExcelPackage(file.InputStream))
{
ExcelWorkbook workbook = package.Workbook;
if (workbook != null)
{
ExcelWorksheet worksheet = workbook.Worksheets.FirstOrDefault();
if (worksheet != null)
{
list = worksheet.ImportExcelToList<FundraiserStudentListModel>();
}
}
}
}
catch (Exception err)
{
//save error log
}
}
return list;
}
FundraiserStudentListModel here:
public class FundraiserStudentListModel
{
public string Name { get; set; }
public string Email { get; set; }
public string Phone { get; set; }
}

Working solution with validate email,mobile number
public class ExcelProcessing
{
public List<ExcelUserData> ReadExcel()
{
string path = Config.folderPath + #"\MemberUploadFormat.xlsx";
using (var excelPack = new ExcelPackage())
{
//Load excel stream
using (var stream = File.OpenRead(path))
{
excelPack.Load(stream);
}
//Lets Deal with first worksheet.(You may iterate here if dealing with multiple sheets)
var ws = excelPack.Workbook.Worksheets[0];
List<ExcelUserData> userList = new List<ExcelUserData>();
int colCount = ws.Dimension.End.Column; //get Column Count
int rowCount = ws.Dimension.End.Row;
for (int row = 2; row <= rowCount; row++) // start from to 2 omit header
{
bool IsValid = true;
ExcelUserData _user = new ExcelUserData();
for (int col = 1; col <= colCount; col++)
{
if (col == 1)
{
_user.FirstName = ws.Cells[row, col].Value?.ToString().Trim();
if (string.IsNullOrEmpty(_user.FirstName))
{
_user.ErrorMessage += "Enter FirstName <br/>";
IsValid = false;
}
}
else if (col == 2)
{
_user.Email = ws.Cells[row, col].Value?.ToString().Trim();
if (string.IsNullOrEmpty(_user.Email))
{
_user.ErrorMessage += "Enter Email <br/>";
IsValid = false;
}
else if (!IsValidEmail(_user.Email))
{
_user.ErrorMessage += "Invalid Email Address <br/>";
IsValid = false;
}
}
else if (col ==3)
{
_user.MobileNo = ws.Cells[row, col].Value?.ToString().Trim();
if (string.IsNullOrEmpty(_user.MobileNo))
{
_user.ErrorMessage += "Enter Mobile No <br/>";
IsValid = false;
}
else if (_user.MobileNo.Length != 10)
{
_user.ErrorMessage += "Invalid Mobile No <br/>";
IsValid = false;
}
}
else if (col == 4)
{
_user.IsAdmin = ws.Cells[row, col].Value?.ToString().Trim();
if (string.IsNullOrEmpty(_user.IsAdmin))
{
_user.IsAdmin = "0";
}
}
_user.IsValid = IsValid;
}
userList.Add(_user);
}
return userList;
}
}
public static bool IsValidEmail(string email)
{
Regex regex = new Regex(#"^([a-zA-Z0-9_\-\.]+)#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$",
RegexOptions.CultureInvariant | RegexOptions.Singleline);
return regex.IsMatch(email);
}
}

With this code you won't get an error because a cell is null. it will also cast the data type according to the properties in your class!
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using OfficeOpenXml;
public static class ReadExcel
{
public static List<T> ReadExcelToList<T>(this ExcelWorksheet worksheet) where T : new()
{
List<T> collection = new List<T>();
try
{
DataTable dt = new DataTable();
foreach (var firstRowCell in new T().GetType().GetProperties().ToList())
{
//Add table colums with properties of T
dt.Columns.Add(firstRowCell.Name);
}
for (int rowNum = 2; rowNum <= worksheet.Dimension.End.Row; rowNum++)
{
var wsRow = worksheet.Cells[rowNum, 1, rowNum, worksheet.Dimension.End.Column];
DataRow row = dt.Rows.Add();
foreach (var cell in wsRow)
{
row[cell.Start.Column - 1] = cell.Text;
}
}
//Get the colums of table
var columnNames = dt.Columns.Cast<DataColumn>().Select(c => c.ColumnName).ToList();
//Get the properties of T
List<PropertyInfo> properties = new T().GetType().GetProperties().ToList();
collection = dt.AsEnumerable().Select(row =>
{
T item = Activator.CreateInstance<T>();
foreach (var pro in properties)
{
if (columnNames.Contains(pro.Name) || columnNames.Contains(pro.Name.ToUpper()))
{
PropertyInfo pI = item.GetType().GetProperty(pro.Name);
pro.SetValue(item, (row[pro.Name] == DBNull.Value) ? null : Convert.ChangeType(row[pro.Name], (Nullable.GetUnderlyingType(pI.PropertyType) == null) ? pI.PropertyType : Type.GetType(pI.PropertyType.GenericTypeArguments[0].FullName)));
}
}
return item;
}).ToList();
}
catch (Exception ex)
{
//Save error log
}
return collection;
}
}
How to call this function? please view below code;
public List<Users> GetStudentsFromExcel(HttpPostedFileBase file)
{
List<Users> list = new List<Users>();
if (file != null)
{
try
{
using (ExcelPackage package = new ExcelPackage(file.InputStream))
{
ExcelWorkbook workbook = package.Workbook;
if (workbook != null)
{
ExcelWorksheet worksheet = workbook.Worksheets.FirstOrDefault();
if (worksheet != null)
{
list = worksheet.ReadExcelToList<Users>();
//Your code
}
}
}
}
catch (Exception ex)
{
//Save error log
}
}
return list;
}
public class Users
{
public string Code { get; set; }
public string Name { get; set; }
public string Email { get; set; }
public string Phone { get; set; }
public string Address { get; set; }
public DateTime CreatedAt { get; set; }
}
Hope to help someone!

Print lists in a list to excel, randomly stops printing after 0.5-6 lists. Comexpection 0x800AC472

First of all I have have some codes which is filling some lists of strings, after that it puts all the lists in 1 big list. Now when I want to print those lists in my excel sheets, it stops after pint half of the first list, or stops after print 5 and a half list, and it says: Exception from HRESULT: 0x800AC472.
There are already 30 tabs in the excel doc, so that is not the problem. Feel free to rename this title, Ihad no idea how to call this problem.
This is how I print my lists in excel:
for (int i = 0; i < ListofLists.Count; i++)
{
for (int j = 1; j <= ListofLists[i].Count; j++)
{
excelDataHandler.excel_setValue("A" + j, ListofLists[i][j-1], "", (i+1));
//A = cell, data of list, color of cell, sheetnumber
}
}
excel_setValue method:
public void excel_setValue(string cellname, string value, string color, int workSheet)
{
((Microsoft.Office.Interop.Excel._Worksheet)newWorkbook_First.Sheets[workSheet]).get_Range(cellname).set_Value(Type.Missing, value);
if (color == "red")
{
newSheets.get_Range(cellname).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Red);
}
}
I would appriciate any help with this problem. Thanks in asvance!

Here is my reflection code.
public static DataTable ClassToDataTable<T>() where T : class
{
Type classType = typeof(T);
List<PropertyInfo> propertyList = classType.GetProperties().ToList();
if (propertyList.Count < 1)
{
return new DataTable();
}
string className = classType.UnderlyingSystemType.Name;
DataTable result = new DataTable(className);
foreach (PropertyInfo property in propertyList)
{
DataColumn col = new DataColumn();
col.ColumnName = property.Name;
Type dataType = property.PropertyType;
if (IsNullable(dataType))
{
if (dataType.IsGenericType)
{
dataType = dataType.GenericTypeArguments.FirstOrDefault();
}
}
else
{ // True by default
col.AllowDBNull = false;
}
col.DataType = dataType;
result.Columns.Add(col);
}
return result;
}
public static DataTable ClassListToDataTable<T>(List<T> ClassList) where T : class
{
DataTable result = ClassToDataTable<T>();
if (result.Columns.Count < 1)
{
return new DataTable();
}
if (ClassList.Count < 1)
{
return result;
}
foreach (T item in ClassList)
{
ClassToDataRow(ref result, item);
}
return result;
}
public static void ClassToDataRow<T>(ref DataTable Table, T Data) where T : class
{
Type classType = typeof(T);
string className = classType.UnderlyingSystemType.Name;
// Checks that the table name matches the name of the class.
// There is not required, and it may be desirable to disable this check.
// Comment this out or add a boolean to the parameters to disable this check.
if (!Table.TableName.Equals(className))
{
return;
}
DataRow row = Table.NewRow();
List<PropertyInfo> propertyList = classType.GetProperties().ToList();
foreach (PropertyInfo prop in propertyList)
{
if (Table.Columns.Contains(prop.Name))
{
if (Table.Columns[prop.Name] != null)
{
row[prop.Name] = prop.GetValue(Data, null);
}
}
}
Table.Rows.Add(row);
}
public static bool IsNullable(Type Input)
{
if (!Input.IsValueType) return true; // Is a ref-type, such as a class
if (Nullable.GetUnderlyingType(Input) != null) return true; // Nullable
return false; // Must be a value-type
}

How to convert a LINQ query result to a DataTable dynamically?

How to convert a LINQ query result to a DataTable dynamically?
There are solutions where you create another class and specify the column names, but I want the flexibility to change the LINQ structure like column names, column quantities, and have a DataTable generated with the columns names automatically.
Thanks

I've included an extension method that I use with SqlBulkCopy that should do the job, but I'd like to ask why you want to this conversion. There are a very limited number of cases (SqlBulkCopy being one) where a list of objects can't do everything a datatable can. You can use them as binding sources for most controls ... just curious.
public static DataTable toDataTable<T>(this IEnumerable<T> value, List<string> exclusionList)
where T : class
{
var dataTable = new DataTable();
var type = typeof(T);
var properties = type.GetProperties().Where(x => !exclusionList.Contains(x.Name)).ToList();
foreach (var propertyInfo in properties)
{
var propertyType = propertyInfo.PropertyType;
if (!propertyType.IsScalar())
continue;
var nullableType = Nullable.GetUnderlyingType(propertyType);
propertyType = nullableType ?? propertyType;
var dataColumn = new DataColumn(propertyInfo.Name, propertyType);
if (nullableType != null)
dataColumn.AllowDBNull = true;
dataTable.Columns.Add(dataColumn);
}
foreach (var row in value)
{
var dataRow = dataTable.NewRow();
foreach (var property in properties)
{
var safeValue = property.GetValue(row, null) ?? DBNull.Value;
dataRow[property.Name] = safeValue;
}
dataTable.Rows.Add(dataRow);
}
return dataTable;
}

Look into the MoreLinq Nuget package. It has a function ToDataTable()
var LinqResults = from ......;
DataTable dt_Results = LinqResults.ToDataTable();
https://code.google.com/p/morelinq/
It has other VERY useful functions as well:
https://code.google.com/p/morelinq/wiki/OperatorsOverview

They key is to use the LINQ query result as its Implemented IList interface.
If you receive the result as a parameter on a method as an IList object, you can access its columns and rows, this way:
var props = item.GetType().GetProperties();
Refer to this example, it's a small class which please note the it just abstracts the creation of the DataTable, and there is a static method inside called "LINQToDataTable" which you should use.
Step 1, create a class called "GridHelper" (uses System.Data for DataTable structure)
public class GridHelper
{
private DataTable baseDt;
public GridHelper(string tableName)
{
baseDt = new DataTable(tableName);
}
public DataTable getDataTable()
{
return baseDt;
}
public object[,] getObjToFill()
{
object[,] obj = new object[baseDt.Columns.Count, 2];
for (int i = 0; i < baseDt.Columns.Count; i++)
{
obj[i, 0] = baseDt.Columns[i].ColumnName;
}
return obj;
}
public void addColumn(string colName, Type valueType)
{
baseDt.Columns.Add(colName, valueType);
}
public void addRow(object[,] values)
{
DataRow newRow = baseDt.NewRow();
for (int i = 0; i < values.Length / 2; i++)
{
bool colFound = false;
for (int j = 0; j < baseDt.Columns.Count; j++)
{
if (baseDt.Columns[j].ColumnName == values[i, 0].ToString())
{
colFound = true;
break;
}
}
if (colFound == false)
{
throw new Exception("The column " + values[i, 0].ToString() + " has not been added yet.");
}
newRow[values[i, 0].ToString()] = values[i, 1];
}
baseDt.Rows.Add(newRow);
}
public static DataTable LINQToDataTable<T>(T objToList) where T : System.Collections.IList
{
GridHelper ghResult = new GridHelper("Report");
foreach (Object item in objToList)
{
var props = item.GetType().GetProperties();
foreach (var prop in props)
{
ghResult.addColumn(prop.Name, typeof(string));
//prop.Name
//prop.GetValue(item)
}
break;
}
object[,] obj = ghResult.getObjToFill();
foreach (Object item in objToList)
{
var props = item.GetType().GetProperties();
int index = 0;
foreach (var prop in props)
{
//ReportValue(prop.Name, prop.GetValue(item, null));
//prop.Name
obj[index, 1] = prop.GetValue(item);
index++;
}
ghResult.addRow(obj);
}
return ghResult.getDataTable();
}
}
Usage:
var listaReporte =
(from t in dbContext.TablaPruebas
select new
{
Name = t.name,
Score = t.score
}
) .ToList();
DataTable dt = Library.GridHelper.LINQToDataTable(listaReporte);
And that is, use your DataTable as you wish, on a GridView or DataGridView

Jump out from Inner-Foreach to Outer-Foreach, Keep Inner-Foreach where you left it

I have the following code:
foreach (XNode rowXml in elements.Nodes())
{
foreach (DataRow rowDB in dataSetDB.Tables[0].Rows)
{
string itemDB = rowDB[0].ToString().ToUpper();
string itemXml = rowXml.ToString().ToUpper();
if (itemDB == itemXml)
{
//If itemDB == itemXml; jump to Outer_Foreach
}
if (itemDB != itemXml)
{
//If itemDB != itemXml; jump to Outer_Foreach
}
}
How is it possible to get out of Inner-Foreach and up to Outer-Foreach, and still keep both foreach where you left it. I am looping through a DB and XML table rows. Break; completley jumps out of the Inner-Foreach and im not able to catch where I left it, so I start back on index[0], when I loop through it over and over again.

It sounds like you need 'for' loop.
int i = 0;
int k = 0;
bool shouldBreak;
var nodes = elements.Nodes();
var rows = dataSetDB.Tables[0].Rows;
for (i = 0; i < nodes.Count(); i++)
{
for(k = 0; k < rows.Count(); k++)
{
string itemDB = rows[k][0].ToString().ToUpper();
string itemXml = nodes[i].ToString().ToUpper();
if (itemDB == itemXml)
{
shouldBreak = true;
break;
}
if (itemDB != itemXml)
{
shouldBreak = true;
break;
}
}
if (toBreak)
break;
}
Now if you'll break the inner loop can know where it broke by accessing i and k

This answer is stolen from this answer here. What you want to achieve is a zip operation. For more information see the answer that I linked.
var xmlNodes = elements.Nodes();
var dbNodes = dataSetDB.Tables[0].Rows;
var xmlAndDB = xmlNodes.Zip(dbNodes , (x, d) => new { xNode = x, dNode = d });
foreach(var xd in xmlAndDB )
{
Console.WriteLine(xd.xNode + xd.dNode);
string itemDB = xd.dNode[0].ToString().ToUpper();
string itemXml = xd.xNode.ToString().ToUpper();
if (itemDB == itemXml)
{
//If itemDB == itemXml;
}
else /* if (itemDB != itemXml) */
{
//If itemDB != itemXml;
}
}