How do you programmatically check if a spreadsheet has headers in C# - c#

I am creating a winform application where every day, a user will select a xlsx file with the day's shipping information to be merged with our invoicing data.
The challenge I am having is when the user does not download the xlsx file with the specification that the winform data requires. (I wish I could eliminate this step with an API connection but sadly I cannot)
My first step is checking to see if the xlsx file has headers to that my file path is valid
Example
string connString = "provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + *path* + "';Extended Properties='Excel 12.0;HDR=YES;';";
Where path is returned from an OpenFileDialog box
If the file was chosen wasn't downloaded with headers the statement above throws an exception.
If change HDR=YES; to HDR=NO; then I have trouble identifying the columns I need and if the User bothered to include the correct ones.
My code then tries to load the data into a DataTable
private void loadRows()
{
for (int i = 0; i < deliveryTable.Rows.Count; i++)
{
DataRow dr = deliveryTable.Rows[i];
int deliveryId = 0;
bool result = int.TryParse(dr[0].ToString(), out deliveryId);
if (deliveryId > 1 && !Deliveries.ContainsKey(deliveryId))
{
var delivery = new Delivery(deliveryId)
{
SalesOrg = Convert.ToInt32(dr[8]),
SoldTo = Convert.ToInt32(dr[9]),
SoldName = dr[10].ToString(),
ShipTo = Convert.ToInt32(dr[11]),
ShipName = dr[12].ToString(),
};
Which all works only if the columns are in the right place.
If they are not in the right place my thought is to display a message to the user to get the right information
Does anyone have any suggestions?
(Sorry, first time posting a question and still learning to think through it)

I guess you're loading the spreadsheet into a Datatable? Hard to tell with one line of code. I would use the columns collection in the datatable and check to see if all the columns you want are there. Sample code to enumerate the columns below.
private void PrintValues(DataTable table)
{
foreach(DataRow row in table.Rows)
{
foreach(DataColumn column in table.Columns)
{
Console.WriteLine(row[column]);
}
}
}

private void GetExcelSheetForUpload(string PathName, string UploadExcelName)
{
string excelFile = "DateExcel/" + PathName;
OleDbConnection objConn = null;
System.Data.DataTable dt = null;
try
{
DataSet dss = new DataSet();
String connString = "Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=True;Extended Properties=Excel 12.0 Xml;Data Source=" + PathName;
objConn = new OleDbConnection(connString);
objConn.Open();
dt = objConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dt == null)
{
return;
}
String[] excelSheets = new String[dt.Rows.Count];
int i = 0;
foreach (DataRow row in dt.Rows)
{
if (i == 0)
{
excelSheets[i] = row["TABLE_NAME"].ToString();
OleDbCommand cmd = new OleDbCommand("SELECT * FROM [" + excelSheets[i] + "]", objConn);
OleDbDataAdapter oleda = new OleDbDataAdapter();
oleda.SelectCommand = cmd;
oleda.Fill(dss, "TABLE");
}
i++;
}
grdExcel.DataSource = dss.Tables[0].DefaultView;
grdExcel.DataBind();
lblTotalRec.InnerText = Convert.ToString(grdExcel.Rows.Count);
}
catch (Exception ex)
{
ViewState["Fuletypeidlist"] = "0";
grdExcel.DataSource = null;
grdExcel.DataBind();
}
finally
{
if (objConn != null)
{
objConn.Close();
objConn.Dispose();
}
if (dt != null)
{
dt.Dispose();
}
}
}
if (grdExcel.HeaderRow.Cells[0].Text.ToString() == "CODE")
{
GetExcelSheetForEmpl(PathName);
}
else
{
divStatusMsg.Style.Add("display", "");
divStatusMsg.Attributes.Add("class", "alert alert-danger alert-dismissable");
divStatusMsg.InnerText = "ERROR !!... Upload Excel Sheet in header Defined Format ";
}

Related

Get first sheet name within excel workbook

I'm trying to get the name of the first sheet of an excel workbook.
Instead of getting the sheets name in the order as it appears in the Excel workbook it appears sorted alphabetically.
Does anyone have an idea to get the names not sorted??
private String[] GetExcelSheetNames(string excelFile)
{
OleDbConnection objConn = null;
System.Data.DataTable dt = null;
try
{
// Connection String. Change the excel file to the file you
// will search.
String connString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
"Data Source=" + excelFile + ";Extended Properties=Excel 8.0;";
// Create connection object by using the preceding connection string.
objConn = new OleDbConnection(connString);
// Open connection with the database.
objConn.Open();
// Get the data table containg the schema guid.
dt = objConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if(dt == null)
{
return null;
}
String[] excelSheets = new String[dt.Rows.Count];
int i = 0;
// Add the sheet name to the string array.
foreach(DataRow row in dt.Rows)
{
excelSheets[i] = row["TABLE_NAME"].ToString();
i++;
}
// Loop through all of the sheets if you want too...
for(int j=0; j < excelSheets.Length; j++)
{
// Query each excel sheet.
}
return excelSheets;
}
catch(Exception ex)
{
return null;
}
finally
{
// Clean up.
if(objConn != null)
{
objConn.Close();
objConn.Dispose();
}
if(dt != null)
{
dt.Dispose();
}
}
}
I already get a solution with my question.
//get sheet number 1 name
var excelFile = Path.GetFullPath(llFileName);
var excel = new Excel.Application();
var workbook = excel.Workbooks.Open(llFileName);
var sheet = (Excel.Worksheet)workbook.Worksheets.Item[1]; // 1 is the first item, this is NOT a zero-based collection
string sheetName = sheet.Name;
Hope it help for the other

Calculate Excel value before import to SQL Server

I have problem about import to SQL Server, the scenario is to import excel file and calculate the value in column 3 and 4 (produce column 5) of the imported excel file. In my case, the calculation is in C#, not in excel. And then import to SQL Server (ASP.Net + C#). Any idea how to do this ?
This is my code (it's still give me error)
protected void btnImport_Click(object sender, EventArgs e)
{
if (FileUpload1.HasFile)
{
string FileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
string Extension = Path.GetExtension(FileUpload1.PostedFile.FileName);
if (Extension == ".xlsx")
{
string path = string.Concat((Server.MapPath("~/tampung/" + FileUpload1.FileName)));
FileUpload1.PostedFile.SaveAs(path);
//make connection to excel workBook
using (OleDbConnection oledbcon = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=Excel 12.0;"))
{
OleDbCommand cmd = new OleDbCommand("SELECT * FROM [Sheet1$]", oledbcon);
OleDbDataAdapter ObjAdapter1 = new OleDbDataAdapter(cmd);
oledbcon.Open();
using (DbDataReader dr = cmd.ExecuteReader())
{
DataTable DT = new DataTable();
DT.Load(dr);
for (int i = 0; i < DT.Rows.Count; i++)
{
string Year = DT.Rows[i][0].ToString();
string StudentName = DT.Rows[i][1].ToString();
string Semester = DT.Rows[i][2].ToString();
decimal Value1 = Convert.ToDecimal(DT.Rows[i][3]);
decimal Value2 = Convert.ToDecimal(DT.Rows[i][4]);
decimal AverageValue = Convert.ToDecimal((Value1 + Value2) / 2);
}
string conString = #"Data Source=PETRELLI;Initial Catalog=demo;Integrated Security=True";
SqlBulkCopy bulkInsert = new SqlBulkCopy(conString);
bulkInsert.DestinationTableName = "student";
bulkInsert.WriteToServer(dr);
oledbcon.Close();
Array.ForEach(Directory.GetFiles(Server.MapPath("~/temp/")), File.Delete);
Label1.Text = "Succeeded";
}
}
}
else
{
Label1.Text = "Hi, it's error";
}
}
else
{
Label1.Text = "Please choose the right file excel";
}
}
The error should be coming from this line
bulkInsert.WriteToServer(dr);
This is happening because DT.Load(dr), that you called earlier, have looped through the dr already and has moved the pointer to the end, after which you can not use the dr again.
DT.Load(dr); //<-- this line already looped through the dr. dr can't be used after this line
Solution
Use the DT instead of dr since you already have DT populated with the required data by calling DT.Load(dr)

how to know which excel sheet is empty using oledb c#?

I'm getting excel sheet name but just the sheet that has data.
String fpath = "Provider=Microsoft.ACE.OLEDB.12.0; data source=" +tbpath.Text+ ";Extended Properties='Excel 12.0 Xml;HDR=YES';";
file = new OleDbConnection(fpath);
file.Open();
dt = file.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dt == null)
{
//return null;
}
cbsheet.Enabled = true;
//String[] excelSheets = new String[dt.Rows.Count];
//int i = 0;
// Add the sheet name to the string array.
foreach (DataRow row in dt.Rows)
{
if (row["TABLE_NAME"].ToString().Contains("$") )//checks whether row contains '_xlnm#_FilterDatabase' or sheet name(i.e. sheet name always ends with $ sign)
{
cbsheet.Items.Add(row["TABLE_NAME"].ToString());
}
}
//return excelSheets;
}
catch (Exception ex)
{
MessageBox.Show("ERROR: "+ex);
}
You could check each sheet for rows i.e.
try
{
foreach (DataRow row in dt.Rows)
{
if (row["TABLE_NAME"].ToString().Contains("$") )
{
OleDbCommand cmd = new OleDbCommand(
"select * from [" + row["TABLE_NAME"].ToString() + "]", file);
using (DbDataReader dr = cmd.ExecuteReader())
{
if (dr.HasRows)
{
cbsheet.Items.Add(row["TABLE_NAME"].ToString());
}
dr.close();
}
}
}
}
catch (Exception ex)
{
MessageBox.Show("ERROR: "+ex);
}
You can just exclude them from getting added.
I used this code to filter out empty sheets. Turns out
they are sheets that shouldn't be accessed by the user.
You can solve this problem in 2 ways.
a. Ignore them
b. Drop down the sheets.
I would highly suggest going with the former.
Use this code;
if (!dt.Rows[i]["Table_Name"].ToString().Contains("FilterDatabase") && !dt.Rows[i]["Table_Name"].ToString().EndsWith("$'"))
{
}

How can I read the rows of an Excel csv or xls file into an ASP.NET app from a remote location using C#?

Here's my situation. I'm designing a program that takes Excel files (which may be in csv, xls, or xlsx format) from a remote network drive, processes the data, then outputs and stores the results of that process. The program provides a listbox of filenames that are obtained from the remote network drive folder using the method detailed in the accepted answer here. Once the user selects a filename from the listbox, I want the program to find the file and obtain the information from it to do the data processing. I have tried using this method to read the data from the Excel file while in a threaded security context, but that method just fails without giving any kind of error. It seems to not terminate. Am I going about this the wrong way?
Edit - (Final Notes: I have taken out the OleDbDataAdapter and replaced it with EPPlus handling.)
I was able to scrub sensitive data from the code, so here it is:
protected void GetFile(object principalObj)
{
if (principalObj == null)
{
throw new ArgumentNullException("principalObj");
}
IPrincipal principal = (IPrincipal)principalObj;
Thread.CurrentPrincipal = principal;
WindowsIdentity identity = principal.Identity as WindowsIdentity;
WindowsImpersonationContext impersonationContext = null;
if (identity != null)
{
impersonationContext = identity.Impersonate();
}
try
{
string fileName = string.Format("{0}\\" + Files.SelectedValue, #"RemoteDirectoryHere");
string connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.14.0; data source={0}; Extended Properties=Excel 14.0;", fileName);
OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM Sheet1", connectionString);
DataSet ds = new DataSet();
adapter.Fill(ds, "Sheet1");
dataTable = ds.Tables["Sheet1"];
}
finally
{
if (impersonationContext != null)
{
impersonationContext.Undo();
}
}
}
Additional Edit
Now xlsx files have been added to the mix.
Third Party
Third party solutions are not acceptable in this case (unless they allow unrestricted commercial use).
Attempts - (Final Notes: Ultimately I had to abandon OleDb connections.)
I have tried all of the different connection strings offered, and I have tried them with just one file type at a time. None of the connection strings worked with any of the file types.
Permissions
The User does have access to the file and its directory.
Your connection string might be the issue here. As far as I know, there isn't 1 that can read all xls, csv, and xlsx. I think you're using the XLSX connection string.
When I read xls, i use the following connection string:
#"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + sFilePath + ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1;'"
Having said that, I recommend using a 3rd party file reader/parser to read XLS and CSV since, from my experience, OleDbDataAdapter is wonky depending on the types of data that's being read (and how mixed they are within each column).
For XLS, try NPOI https://code.google.com/p/npoi/
For CSV, try http://www.codeproject.com/Articles/9258/A-Fast-CSV-Reader
For XLSX, try EPPlus http://epplus.codeplex.com/
I've had great success with the above libraries.
Is it really important that you use an OleDb interface for this? I've always done it with Microsoft.Office.Excel.Interop, to wit:
using System;
using Microsoft.Office.Interop.Excel;
namespace StackOverflowExample
{
class Program
{
static void Main(string[] args)
{
var app = new Application();
var wkbk = app.Workbooks.Open(#"c:\data\foo.xls") as Workbook;
var wksht = wkbk.Sheets[1] as Worksheet; // not zero-based!
for (int row = 1; row <= 100; row++) // not zero-based!
{
Console.WriteLine("This is row #" + row.ToString());
for (int col = 1; col <= 100; col++)
{
Console.WriteLine("This is col #" + col.ToString());
var cell = wksht.Cells[row][col] as Range;
if (cell != null)
{
object val = cell.Value;
if (val != null)
{
Console.WriteLine("The value of the cell is " + val.ToString());
}
}
}
}
}
}
}
As you will be dealing with xlsx extension, you should rather opt for the new connection string.
public static string getConnectionString(string fileName, bool HDRValue, bool WriteExcel)
{
string hdrValue = HDRValue ? "YES" : "NO";
string writeExcel = WriteExcel ? string.Empty : "IMEX=1";
return "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + fileName + ";" + "Extended Properties=\"Excel 12.0 xml;HDR=" + hdrValue + ";" + writeExcel + "\"";
}
Above is the code for getting the connection string. First argument expects the actual path for file location. Second argument will decide whether to consider first row values as column headers or not. Third argument helps decide whether you want to open the connection to create and write the data or simply read the data. To read the data set it to "FALSE"
public static ReadData(string filePath, string sheetName, List<string> fieldsToRead, int startPoint, int endPoint)
{
DataTable dt = new DataTable();
try
{
string ConnectionString = ProcessFile.getConnectionString(filePath, false, false);
using (OleDbConnection cn = new OleDbConnection(ConnectionString))
{
cn.Open();
DataTable dbSchema = cn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dbSchema == null || dbSchema.Rows.Count < 1)
{
throw new Exception("Error: Could not determine the name of the first worksheet.");
}
StringBuilder sb = new StringBuilder();
sb.Append("SELECT *");
sb.Append(" FROM [" + sheetName + fieldsToRead[0].ToUpper() + startPoint + ":" + fieldsToRead[1].ToUpper() + endPoint + "] ");
OleDbDataAdapter da = new OleDbDataAdapter(sb.ToString(), cn);
dt = new DataTable(sheetName);
da.Fill(dt);
if (dt.Rows.Count > 0)
{
foreach (DataRow row in dt.Rows)
{
string i = row[0].ToString();
}
}
cn.Dispose();
return fileDatas;
}
}
catch (Exception)
{
}
}
This is for reading 2007 Excel into dataset
DataSet ds = new DataSet();
try
{
string myConnStr = "";
myConnStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=MyDataSource;Extended Properties=\"Excel 12.0;HDR=YES\"";
OleDbConnection myConn = new OleDbConnection(myConnStr);
OleDbCommand cmd = new OleDbCommand("select * from [Sheet1$] ", myConn);
OleDbDataAdapter adapter = new OleDbDataAdapter();
adapter.SelectCommand = cmd;
myConn.Open();
adapter.Fill(ds);
myConn.Close();
}
catch
{ }
return ds;

Reading columns from Excel, reformat cells

I am currently trying to read in cells from an excel spread sheet, and it seems to reformat cells when I don't want it to. I want it to come through as plan text. I have read a couple of solutions to this problem and I have implemented them, but I am still having the same issue.
The reader turns dates in numbers and numbers into dates.
Example:
Friday, January 29, 2016 comes out to be : 42398
and
40.00 comes out to be : 2/9/1900 12:00:00 AM
code:
string stringconn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + files[0] + ";Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO;TypeGuessRows=0;ImportMixedTypes=Text\"";
try {
OleDbConnection conn = new OleDbConnection(stringconn);
OleDbDataAdapter da = new OleDbDataAdapter("SELECT * FROM [CUAnswers$]", conn);
DataTable dt = new DataTable();
try {
printdt(dt);
I have tried
IMEX=0;
HDR=NO;
TypeGuessRows=1;
This is how I am printing out the sheet
public void printdt(DataTable dt) {
int counter1 = 0;
int counter2 = 0;
string temp = "";
foreach (DataRow dataRow in dt.Rows) {
foreach (var item in dataRow.ItemArray) {
temp += " ["+counter1+"]["+counter2+"]"+ item +", ";
counter2++;
}
counter1++;
logger.Debug(temp);
temp = "";
counter2 = 0;
}
}
I had a similar problem, except it was using Interop to read the Excel spreadsheet. This worked for me:
var value = (range.Cells[rowCnt, columnCnt] as Range).Value2;
string str = value as string;
DateTime dt;
if (DateTime.TryParse((value ?? "").ToString(), out dt))
{
// Use the cell value as a datetime
}
Editted to add new ideas
I was going to suggest saving the spreadsheet as comma-separated values. Then Excel converts the cells to text. It is easy to parse a CSV in C#.
That led me to think of how to programmatically do the conversion, which is covered in Convert xls to csv programmatically. Maybe the code in the accepted answer is what you are looking for:
string ExcelFilename = "c:\\ExcelFile.xls";
DataTable worksheets;
string connectionString = #"Provider=Microsoft.Jet.OLEDB.4.0;" + #"Data Source=" + ExcelFilename + ";" + #"Extended Properties=""Excel 8.0;HDR=Yes;IMEX=1""";
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
connection.Open();
worksheets = connection.GetSchema("Tables");
foreach (DataRow row in worksheets.Rows)
{
// For Sheets: 0=Table_Catalog,1=Table_Schema,2=Table_Name,3=Table_Type
// For Columns: 0=Table_Name, 1=Column_Name, 2=Ordinal_Position
string SheetName = (string)row[2];
OleDbCommand command = new OleDbCommand(#"SELECT * FROM [" + SheetName + "]", connection);
OleDbDataAdapter oleAdapter = new OleDbDataAdapter();
oleAdapter.SelectCommand = command;
DataTable dt = new DataTable();
oleAdapter.FillSchema(dt, SchemaType.Source);
oleAdapter.Fill(dt);
for (int r = 0; r < dt.Rows.Count; r++)
{
string type1 = dr[1].GetType().ToString();
string type2 = dr[2].GetType().ToString();
string type3 = dr[3].GetType().ToString();
string type4 = dr[4].GetType().ToString();
string type5 = dr[5].GetType().ToString();
string type6 = dr[6].GetType().ToString();
string type7 = dr[7].GetType().ToString();
}
}
}

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