Develop Reference

Excel file not being written to

I am trying to write to an Excel file using openXML. I followed Microsoft's example to do it. There's only a small difference with the code being that I wish to write number values instead of text.
See the code below :
public void SetSpreadSheet(string filePath)
{
sprdSheet = SpreadsheetDocument.Open(filePath, true);
wrkBook = sprdSheet.WorkbookPart;
wrkSheet = wrkBook.AddNewPart<WorksheetPart>();
wrkSheet.Worksheet = new Worksheet(new SheetData());
wrkSheet.Worksheet.Save();
sheets = wrkBook.Workbook.AppendChild(new Sheets());
sheet = new Sheet() { Id = wrkBook.GetIdOfPart(wrkSheet), SheetId = 1, Name = "test" };
sheets.Append(sheet);
}
Here I use SpreadsheetDocument.Open instead of creating a new one because I aim to write to an existing Excel template in the future.
public void AddData(float data, string columnName, UInt32 rowIndex)
{
var row = new Row() { RowIndex = rowIndex };
wrkSheet.Worksheet.AppendChild(row);
Cell cell = InsertCellInWorksheet(columnName, rowIndex, wrkSheet);
cell.CellValue = new CellValue(data);
cell.DataType = new EnumValue<CellValues>(CellValues.Number);
wrkSheet.Worksheet.Save();
}
There is another method called InsertCellInWorksheet which I took from MSDN example (and decided to not include since it is quite long).
I tested these methods using the following programm:
int column = 10;
int row = 5;
var rnd = new Random();
var xl = new Xl();
xl.SetSpreadSheet(#"path to the file .xlsx");
for(int c = 1; c <= column; c++)
{
for(int r = 1; r <= row; r++)
{
var columnName = Number2String(c, true);
xl.AddData(rnd.Next(10), columnName, (uint)r);
}
}
Console.WriteLine("FINISHED");
Console.ReadLine();
And the result that I get is an empty Excel spreadsheet.
In the MSDN example they use a SharedStringTablePart to write to the Excel spreadsheet, is there an object akin to it that I should use to write numerical data ?
UPDATE
Following mcalex' comment i tried using ClosedXML and succeeded in doing just what I wanted to do. However, I'm still interested in understanding why my file is not being written to so feel free to answer the question.

How can I pass and format an SQL table into an excel using C#

Currently I have a table with 6 rows and 14 columns.
I'm trying to pass that table to my excel document and I have no problem doing that.
My problem is that I can't format it the way I want.
Idealy I want to have 3 rows, blank space and 3 rows again, but I can't do that.
This is the function I'm currently using to format the Sql table. Basically it writes in excel all the rows consecutively.
Instead of doing that I want it to have a black row between row 3 and row 4.
If someone could help I'd very thankful.
private int Export_putDataGeneric(Excel.Worksheet sh, DataTable ds, String D_ReferenceDate, int starting_row = 5, int[] column_mapping = null, bool isNumber = true)
{
int curr_row = 0;
if (column_mapping == null)
{
column_mapping = new int[ds.Columns.Count];
int start_char = 2;
for (int c = 0; c < ds.Columns.Count; c++)
{
column_mapping[c] = start_char;
start_char++;
}
}
var data = new Object[ds.Rows.Count, column_mapping[ds.Columns.Count - 1] - column_mapping[0] + 1];
foreach (DataRow row in ds.Rows)
{
for (int c = 0; c < ds.Columns.Count; c++)
{
data[curr_row, column_mapping[c] - column_mapping[0]] = row[c];
}
curr_row++;
}
int end_row = starting_row + ds.Rows.Count - 1;
Excel.Range beginWrite = sh.Cells[starting_row, column_mapping[0]] as Excel.Range;
Excel.Range endWrite = sh.Cells[end_row, column_mapping[ds.Columns.Count - 1]] as Excel.Range;
Excel.Range sheetData = sh.Range[beginWrite, endWrite];
sheetData.Value2 = data;
if (isNumber) sheetData.NumberFormat = "#,##0.00";
Marshal.ReleaseComObject(beginWrite);
Marshal.ReleaseComObject(endWrite);
Marshal.ReleaseComObject(sheetData);
beginWrite = null;
endWrite = null;
sheetData = null;
return end_row;
}

You can try using Range.Offset.
Check out the Microsoft Documentation
This question on SO might also help.

The source contains no DataRows. error when one iteration in for loop

I am making a program in Visual Studio where you can read in an excel file in a specific format and where my program converts the data from the excel file in a different format and stores it in a database table.
Below you can find a part of my code where something strange happens
//copy schema into new datatable
DataTable _longDataTable = _library.Clone();
foreach (DataRow drlibrary in _library.Rows)
{
//count number of variables in a row
string check = drlibrary["Check"].ToString();
int varCount = check.Length - check.Replace("{", "").Length;
int count_and = 0;
if (check.Contains("and") || check.Contains("or"))
{
count_and = Regex.Matches(check, "and").Count;
varCount = varCount - count_and;
}
//loop through number of counted variables in order to add rows to long datatable (one row per variable)
for (int i = 1; i <= varCount; i++)
{
var newRow = _longDataTable.NewRow();
newRow.ItemArray = drlibrary.ItemArray;
string j = i.ToString();
//fill variablename with variable number
if (i < 10)
{
newRow["VariableName"] = "Variable0" + j;
}
else
{
newRow["VariableName"] = "Variable" + j;
}
}
}
When varCount equals 1, I get the following error message when running the program after inserting an excel file
The source contains no DataRows.
I don't know why I can't run the for loop with just one iteration. Anyone who can help me?

'System.AccessViolationException' occurred

UPDATED: added full block of code where error occurs
UPDATE 2: I found a weird anomaly. The code has now been continuously breaking on that line, when the tabName variable equals "service line prior year". This morning, for grins, I changed the tab name to "test", so in turn the tabName variable equals "test", and it worked more often then not. I am really at a loss.
I have researched a ton and can't find anything that addresses what is happening in my code. It happens randomly though. Sometimes it doesn't happen, then other times it happens in the same spot, but all on this part of the code (on the line templateSheet = templateBook.Sheets[tabName];):
public void ExportToExcel(DataSet dataSet, string filePath, int i, int h, Excel.Application excelApp)
{
//create the excel definitions again.
//Excel.Application excelApp = new Excel.Application();
//excelApp.Visible = true;
FileInfo excelFileInfo = new FileInfo(filePath);
Boolean fileOpenTest = IsFileOpen(excelFileInfo);
Excel.Workbook templateBook;
Excel.Worksheet templateSheet;
//check to see if the template is already open, if its not then open it,
//if it is then bind it to work with it
if (!fileOpenTest)
{ templateBook = excelApp.Workbooks.Open(filePath); }
else
{ templateBook = (Excel.Workbook)System.Runtime.InteropServices.Marshal.BindToMoniker(filePath); }
//this grabs the name of the tab to dump the data into from the "Query Dumps" Tab
string tabName = lstQueryDumpSheet.Items[i].ToString();
templateSheet = templateBook.Sheets[tabName];
excelApp.Calculation = Excel.XlCalculation.xlCalculationManual;
templateSheet = templateBook.Sheets[tabName];
// Copy DataTable
foreach (System.Data.DataTable dt in dataSet.Tables)
{
// Copy the DataTable to an object array
object[,] rawData = new object[dt.Rows.Count + 1, dt.Columns.Count];
// Copy the values to the object array
for (int col = 0; col < dt.Columns.Count; col++)
{
for (int row = 0; row < dt.Rows.Count; row++)
{ rawData[row, col] = dt.Rows[row].ItemArray[col]; }
}
// Calculate the final column letter
string finalColLetter = string.Empty;
string colCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int colCharsetLen = colCharset.Length;
if (dt.Columns.Count > colCharsetLen)
{ finalColLetter = colCharset.Substring((dt.Columns.Count - 1) / colCharsetLen - 1, 1); }
finalColLetter += colCharset.Substring((dt.Columns.Count - 1) % colCharsetLen, 1);
//this grabs the cell address from the "Query Dump" sheet, splits it on the '=' and
//pulls out only the cell address (i.e., "address=a3" becomes "a3")
string dumpCellString = lstQueryDumpText.Items[i].ToString();
string dumpCell = dumpCellString.Split('=').Last();
//referts to the range in which we are dumping the DataSet. The upper right hand cell is
//defined by the 'dumpCell' varaible and the bottom right cell is defined by the
//final column letter and the count of rows.
string firstRef = "";
string baseRow = "";
if (char.IsLetter(dumpCell, 1))
{
char[] createCellRef = dumpCell.ToCharArray();
firstRef = createCellRef[0].ToString() + createCellRef[1].ToString();
for (int z = 2; z < createCellRef.Count(); z++)
{
baseRow = baseRow + createCellRef[z].ToString();
}
}
else
{
char[] createCellRef = dumpCell.ToCharArray();
firstRef = createCellRef[0].ToString();
for (int z = 1; z < createCellRef.Count(); z++)
{
baseRow = baseRow + createCellRef[z].ToString();
}
}
int baseRowInt = Convert.ToInt32(baseRow);
int startingCol = ColumnLetterToColumnIndex(firstRef);
int endingCol = ColumnLetterToColumnIndex(finalColLetter);
int finalCol = startingCol + endingCol;
string endCol = ColumnIndexToColumnLetter(finalCol - 1);
int endRow = (baseRowInt + (dt.Rows.Count - 1));
string cellCheck = endCol + endRow;
string excelRange;
if (dumpCell.ToUpper() == cellCheck.ToUpper())
{
excelRange = string.Format(dumpCell + ":" + dumpCell);
}
else
{
excelRange = string.Format(dumpCell + ":{0}{1}", endCol, endRow);
}
//this dumps the cells into the range on Excel as defined above
templateSheet.get_Range(excelRange, Type.Missing).Value2 = rawData;
//checks to see if all the SQL queries have been run from the "Query Dump" tab, if not, continue
//the loop, if it is the last one, then save the workbook and move on.
if (i == lstSqlAddress.Items.Count - 1)
{
excelApp.Calculation = Excel.XlCalculation.xlCalculationAutomatic;
/*Run through the value save sheet array then grab the address from the corresponding list
place in the address array. If the address reads "whole sheet" then save the whole page,
else set the addresses range and value save that.*/
//for (int y = 0; y < lstSaveSheet.Items.Count; y++)
//{
// MessageBox.Show("Save Sheet: " + lstSaveSheet.Items[y] + "\n" + "Save Address: " + lstSaveRange.Items[y]);
//}
//run the macro to hide the unused columns
excelApp.Run("ReportMakerExecute");
//save excel file as hospital name and move onto the next
SaveTemplateAs(templateBook, h);
//close the open Excel App before looping back
//Marshal.ReleaseComObject(templateSheet);
//Marshal.ReleaseComObject(templateBook);
//templateSheet = null;
//templateBook = null;
//GC.Collect();
//GC.WaitForPendingFinalizers();
}
//Close excel Applications
//excelApp.Quit();
//Marshal.ReleaseComObject(templateSheet);
//Marshal.FinalReleaseComObject(excelApp);
//excelApp = null;
//templateSheet = null;
// GC.Collect();
//GC.WaitForPendingFinalizers();
}
}
The try/catch block is of no use either. This is the error:
"An unhandled exception of type 'System.AccessViolationException' occurred inSQUiRE (Sql QUery REtriever) v1.exe. Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt."

System.AccessViolationException would normally happen when you try to access an unallocated memory in a native code (not .NET). Then .NET translates it to the managed world as this exception.
Your code itself does not have any unsafe block. So access violation must me happening inside Excel.
Given the fact that it sometimes happens, some times not, I would say that it can be caused by a parallel Excel usage (I think the Excel COM is not thread-safe).
I would recommend you putting all your code inside a lock block, to prevent Excel from begin used in parallel. Something like this:
public void ExportToExcel(DataSet dataSet, string filePath, int i, int h, Excel.Application excelApp)
{
lock(this.GetType()) // You can change here to other instance to me used a mutex
{
// Your original code here
}
}

So long story, three days of testing longer, it was because of an excel file that was trying to open and fill with SQL results. The buffer was filling up and causing an exception...it just happened at the same point in every run because the load time for the excel file was the determining factor in it working or failing.
So after the load i just added a delaying do...while that checked to see if the file was accessible or not and it stopped the failures. fileOpenTest was taken from here
do
{
Task.Delay(2000);
}
while(!fileOpenTest);

How to specify format for individual cells with Excel.Range.set_Value()

When I write a whole table into an excel worksheet, I know to work with a whole Range at once instead of writing to individual cells. However, is there a way to specify format as I'm populating the array I'm going to export to Excel?
Here's what I do now:
object MissingValue = System.Reflection.Missing.Value;
Excel.Application excel = new Excel.Application();
int rows = 5;
int cols = 5;
int someVal;
Excel.Worksheet sheet = (Excel.Worksheet)excel.Workbooks.Add(MissingValue).Sheets[1];
Excel.Range range = sheet.Range("A1", sheet.Cells(rows,cols));
object[,] rangeData = new object[rows,cols];
for(int r = 0; r < rows; r++)
{
for(int c = 0; c < cols; c++)
{
someVal = r + c;
rangeData[r,c] = someVal.ToString();
}
}
range.set_Value(MissingValue, rangeData);
Now suppose that I want some of those numbers to be formatted as percentages. I know I can go back on a cell-by-cell basis and change the formatting, but that seems to defeat the whole purpose of using a single Range.set_Value() call. Can I make my rangeData[,] structure include formatting information, so that when I call set_Value(), the cells are formatted in the way I want them?
To clarify, I know I can set the format for the entire Excel.Range object. What I want is to have a different format specified for each cell, specified in the inner loop.

So here's the best "solution" I've found so far. It isn't the nirvanna I was looking for, but it's much, much faster than setting the format for each cell individually.
// 0-based indexes
static string RcToA1(int row, int col)
{
string toRet = "";
int mag = 0;
while(col >= Math.Pow(26, mag+1)){mag++;}
while (mag>0)
{
toRet += System.Convert.ToChar(64 + (byte)Math.Truncate((double)(col/(Math.Pow(26,mag)))));
col -= (int)Math.Truncate((double)Math.Pow(26, mag--));
}
toRet += System.Convert.ToChar(65 + col);
return toRet + (row + 1).ToString();
}
static Random rand = new Random(DateTime.Now.Millisecond);
static string RandomExcelFormat()
{
switch ((int)Math.Round(rand.NextDouble(),0))
{
case 0: return "0.00%";
default: return "0.00";
}
}
struct ExcelFormatSpecifier
{
public object NumberFormat;
public string RangeAddress;
}
static void DoWork()
{
List<ExcelFormatSpecifier> NumberFormatList = new List<ExcelFormatSpecifier>(0);
object[,] rangeData = new object[rows,cols];
for(int r = 0; r < rows; r++)
{
for(int c = 0; c < cols; c++)
{
someVal = r + c;
rangeData[r,c] = someVal.ToString();
NumberFormatList.Add(new ExcelFormatSpecifier
{
NumberFormat = RandomExcelFormat(),
RangeAddress = RcToA1(rowIndex, colIndex)
});
}
}
range.set_Value(MissingValue, rangeData);
int max_format = 50;
foreach (string formatSpecifier in NumberFormatList.Select(p => p.NumberFormat).Distinct())
{
List<string> addresses = NumberFormatList.Where(p => p.NumberFormat == formatSpecifier).Select(p => p.RangeAddress).ToList();
while (addresses.Count > 0)
{
string addressSpecifier = string.Join(",", addresses.Take(max_format).ToArray());
range.get_Range(addressSpecifier, MissingValue).NumberFormat = formatSpecifier;
addresses = addresses.Skip(max_format).ToList();
}
}
}
Basically what is happening is that I keep a list of the format information for each cell in NumberFormatList (each element also holds the A1-style address of the range it applies to). The original idea was that for each distinct format in the worksheet, I should be able to construct an Excel.Range of just those cells and apply the format to that range in a single call. This would reduce the number of accesses to NumberFormat from (potentially) thousands down to just a few (however many different formats you have).
I ran into an issue, however, because you apparently can't construct a range from an arbitrarily long list of cells. After some testing, I found that the limit is somewhere between 50 and 100 cells that can be used to define an arbitrary range (as in range.get_Range("A1,B1,C1,A2,AA5,....."). So once I've gotten the list of all cells to apply a format to, I have one final while() loop that applies the format to 50 of those cells at a time.
This isn't ideal, but it still reduces the number of accesses to NumberFormat by a factor of up to 50, which is significant. Constructing my spreadsheet without any format info (only using range.set_Value()) takes about 3 seconds. When I apply the formats 50 cells at a time, that is lengthened to about 10 seconds. When I apply the format info individually to each cell, the spreadsheet takes over 2 minutes to finish being constructed!

You can apply a formatting on the range, and then populate it with values you cannot specify formatting in you object[,] array

You apply the formatting to each individual cell within the inner loop via
for(int r = 0; r < rows; r++)
{
for(int c = 0; c < cols; c++)
{
Excel.Range r2 = sheet.Cells( r, c );
r2.xxxx = "";
}
}
Once you have r2, you can change the cell format any way you want.