Develop Reference

How to iterate throgh a specific row in Excel table via Interop?

So, I'm writing a program that is reads table data and puts cells values in a List. I made it, but there is one problem – UsedRange takes all cells on sheet so there is more items then I need and also, when I specify range by ["A:A", Type.Missng] it gives me an exception:
System.ArgumentException: "HRESULT: 0x80070057 (E_INVALIDARG))"
So my question is how to make it correctly?
Code is:
foreach (Excel.Range row in usedRange)
{
for(int i=0; i<lastCell.Row; i++)
{
if (row.Cells[4, i + 1].Value2 != null)
{
personlist.Add(Convert.ToString(row.Cells[4, i + 1].Value2));
}
else { i++; }
}
foreach(var person in personlist) {
Console.WriteLine(person);
}
}
UPD: I need a last used row, that's why I'm using UsedRange. So if there is any alternatives, like, checking if(!=null)? I will gladly try it
Tried to give it specific range, some tries to made a code like here C# - How do I iterate all the rows in Excel._Worksheet?
and here
https://overcoder.net/q/236542/программно-получить-последнюю-заполненную-строку-excel-с-помощью-c
but maybe I'm a dumb one, 'cause there is literally more than one articles about it and non of it works with me

The problem is 'used range' can include empty range (who knows how excel decides that magic number - if you type a letter on some arbitrary row and then delete it Excel can decide that cell is still part of your used range). You want your own custom definition of what a 'usedRange' is, which presumably is the range of non-blank rows. There's two straightforward ways of implementing this yourself (which gives you added control over it should you want to customize it).
You can just filter the list after the fact removing all blank entries. Or you can process the list in reverse, skipping rows till you find one matching your criteria
bool startProcessing = false;
for(int i=lastCell.Row-1; i>=0; i--)
{
if(!startProcessing){//bool is in case you want blank rows in the middle of the file, otherwise check valid row always
//check if valid row
//continue; if not, set startProcessing to true if yes
}
if (row.Cells[4, i + 1].Value2 != null)
{
personlist.Add(Convert.ToString(row.Cells[4, i + 1].Value2));
}
//else { i++; } //this is a bug, will cause a line skip
}
Also, as an aside - when you call i++; in the body of your for loop, it then calls it again in the header of your for loop and i += 2 skipping a row. Use continue; or just remove the else block altogether.
There's probably a way to get a cellRange matching your criteria, but imo doing it yourself can be better - you can ensure it does exactly what you want.

C# Excel VSTO can not convert string to String.Array

I am new to VSTO C# excel add-in. I am looking to find total count of not null/empty rows in a range. My Code looks at the range "A4:E4" and count total number of rows.
This is the code :
private void button1_Click(object sender, RibbonControlEventArgs e)
{
Workbook workbook = Globals.ThisAddIn.GetWorkBook("c:\\temp\\testfile.xlsx");
Worksheet mergeSheet = workbook.Worksheets["Data"];
Excel.Range mergeCells = mergeSheet.Range["A4:E4"];
var colValues = (System.Array)mergeCells.Columns[1].Cells.Value;
var strArray = colValues.OfType<object>().Select(o => o.ToString()).ToArray();
var rowCount = strArray.Length;
}
[public Excel.Workbook GetWorkBook(string pathName)
{
return (Excel.Workbook)Application.Workbooks.Open(pathName);
}][1]
I get error var colValues = (System.Array)mergeCells.Columns[1].Cells.Value;on line :
Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: 'Cannot convert type 'string' to 'System.Array''
It works when I have two rows in my range. I have hardcoded range A4:E4 to produce the error. My excel sheet (testfile.xlsx) looks like below:
Any ideas how do I resolve this?
Same line of code works when I have two rows. Eg and following line is updated
Excel.Range mergeCells = mergeSheet.Range["A4:E5"];

The problem is that Range.Value can return different types of objects. Among others, it can return
a single value of type String, if the range contains a single cell containing a string or
an array of values, if the range contains more than one cell.
The simplest solution would be to count the number of cells and "wrap" the special "single value" case in an array:
var range = mergeCells.Columns[1].Cells;
var values = (range.Count == 1)
? new object[] { range.Value })
: ((Sytem.Array)range.Value).Cast<object>();

This line is causing me trouble, var colValues = (System.Array)mergeCells.Columns[1].Cells.Value
This row has only one value. Note that same line works when mergeCells range has two rows.
Why it does not work for single cell range:
The Value of a single cell is not an array (it's a Long, String, DateTime, etc.) and won't be cast to an array in that manner. You can see this by testing like below:
var myArray = (System.Array)"hello"
This will give same failure for other types:
Why it works for multi-cell range:
The Value of a multi-cell range will return a variant array of the individual cell values, which either is, or can be cast to a System.Array
There may be a better resolution, but at least you should be able to do like:
var colValues;
if (mergeCells.Columns[1].Cells.Count > 1)
{
colValues = (System.Array)mergeCells.Columns[1].Cells.Value;
}
else
{
// NB: you may need to cast other data types to string
// or you could use .Cells[0].Text.Split()
colValues = (System.Array)mergeCells.Columns[1].Cells[0].Value.Split();
}

How to check if cell value is a number

Cells of Excel spreadsheet are read using Microsoft.Office.Interop.Excel object.
I need to find out formatting for number values and apply accordingly.
For instance I have 19.0000 value but when it is read Value2 will be "19" however I need to keep it "19.0000"
Excel.Range sheetRange = xlWorksheet.Range["A1", lastCell];
var cell = sheetRange.Cells[row, col];
cell.Value2 == "19";
There is a NumberFormat property that returns formatting string like "0.0000" that I could use, but I can't find out how to check if cell value is a number.

a bit of a hacky way around it is to add an apostrophe at the beginning - excel wont try to format it then
for instance
var value = 19.0000;
cell.value = "'" + value;

I use this function for that purpose:
public static bool IsValidDecimalNumber(this string s)
{
if (string.IsNullOrWhiteSpace(s)) return false; //blank/null strings aren't valid decimal numbers
return !s.Any(c => !(char.IsDigit(c) || c == '.')) && !(s.Count(c => c == '.') > 1);
}
Edit: to elaborate, it returns false if it's blank/null, then it returns false if any digits aren't a number or a decimal point, and it returns false if there's more than one decimal point. Otherwise, it returns true.

C# - Using OpenXML how to read blank spaces on excel files

I was searching for some solutions but failed to find one, currently I have a problem on reading an excel file using OpenXML. With perfect data, there won't be any problem, but with data with blanks, the columns seems to be moving to the left, producing an error saying that the index was not right since it actually moved to the left. I found a solution wherein you can place in cells in between, but when I tried it, an error saying that an object reference was not set to an instance of an object while reading the certain cell with this code (source is from the answer in here for inserting cells How do I have Open XML spreadsheet "uncollapse" cells in a spreadsheet?)
public static string GetCellValue(SpreadsheetDocument document, Cell cell)
{
SharedStringTablePart stringTablePart = document.WorkbookPart.SharedStringTablePart;
string value = cell.CellValue.InnerXml;
if (cell.DataType != null && cell.DataType.Value == CellValues.SharedString)
{
return stringTablePart.SharedStringTable.ChildElements[Int32.Parse(value)].InnerText;
}
else if (cell == null)
{
return null;
}
else
{
return value;
}
}
any other ways wherein I can read blank cells as blank without moving the data to the left?
All help will be appreciated! :)
Thanks!

In Open XML, xml file does not contain an entry for the blank cell that's why blank cells are skipped. I faced the same problem. The only solution is apply some logic.
For Example:
When we read a cell we can get its ColumnName (A,B,C etc.) by the following code
string cellIndex = GetColumnName( objCurrentSrcCell.CellReference );
where
public static string GetColumnName(string cellReference)
{
// Create a regular expression to match the column name portion of the cell name.
Regex regex = new Regex("[A-Za-z]+");
Match match = regex.Match(cellReference);
return match.Value;
}
you can store these cells in a Hashtable where key can be the cell ColumnName and value can be the object of the cell. And when writing fetch cells from the hash object serially on some basis or your logic like...
you may loop from A to Z and read the cells at particular key like
if(objHashTable.Contains(yourKey))
{
Cell objCell = (Cell) objHashTable[yourKey];
//Insertcell or process cell
}
else
{
//do process for the empty cell like you may add a new blank cell
Cell objCell = new Cell();
//Insert cell or process cell
}
This is the only way to work with open xml. adding a blank cell during reading is a waste of time. You can add more logic according to you
try this. this will definitely work. or if you find a better solution, do tell me
Have a nice day :)

Writing string, numeric data to Excel via C# works, but Excel does not treat numeric data correctly

I'm getting result sets from Sybase that I return to a C# client.
I use the below function to write the result set data to Excel:
private static void WriteData(Excel.Worksheet worksheet, string cellRef, ref string[,] data)
{
Excel.Range range = worksheet.get_Range(cellRef, Missing.Value);
if (data.GetLength(0) != 0)
{
range = range.get_Resize(data.GetLength(0), data.GetLength(1));
range.set_Value(Missing.Value, data);
}
}
The data gets written correctly.
The issue is that since I'm using string array to write data (which is a mixture of strings and floats), Excel highlights every cell that contains numeric data with the message "Number Stored as Text".
How do I get rid of this issue?
Many thanks,
Chapax

Try the following: replace your array of string by an array of object.
var data = new object[2,2];
data[0, 0] = "A";
data[0, 1] = 1.2;
data[1, 0] = null;
data[1, 1] = "B";
var theRange = theSheet.get_Range("D4", "E5");
theRange.Value2 = data;
If I use this code, equivalent to yours:
var data = new string[2,2];
I get the same symptom as you.
As a side benefit, you don't have to cast anything to string: you can fill your array with whatever you want to see displayed.

Try setting the NumberFormat property on the range object.