Develop Reference

How to retrieve efficiently all strings from a large Excel documents

The Excel spreadsheet should be read by .NET. It is very efficient to read all values from the active range by using the property Value. This transfers all values in a two dimensional array, by one single call to Excel.
However reading strings is not possible for a range which contains more than one single cell. Therefor we have to iterate over all cells and use the Text property. This shows very poor performance for larger document.
The reason of using strings rather than values is to obtains the correct format (for instance for dates or the number of digits).
Here is a sample code written in C# to demonstrate the approach.
static void Main(string[] args)
{
Excel.Application xlApp = (Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");
var worksheet = xlApp.ActiveSheet;
var cells = worksheet.UsedRange();
// read all values in array -> fast
object[,] arrayValues = cells.Value;
// create array for text of the same extension
object[,] arrayText = (object[,])Array.CreateInstance(typeof(object),
new int[] { arrayValues.GetUpperBound(0), arrayValues.GetUpperBound(1) },
new int[] { arrayValues.GetLowerBound(0), arrayValues.GetLowerBound(1) });
// read text for each cell -> slow
for (int row = arrayValues.GetUpperBound(0); row <= arrayValues.GetUpperBound(0); ++row)
{
for (int col = arrayValues.GetUpperBound(0); col <= arrayValues.GetUpperBound(1); ++col)
{
object obj = cells[row, col].Text;
arrayText[row, col] = obj;
}
}
}
The question is, if there is a more efficient way to read the complete string content from an Excel document. One idea was to use cells.Copy to copy the content to the clipboard to get it from there. However this has some restrictions and could of course interfere with users which are working with the clipboard at the same time. So I wonder if there are better approaches to solve this performance issue.

You can use code below:
using (MSExcel.Application app = MSExcel.Application.CreateApplication())
{
MSExcel.Workbook book1 = app.Workbooks.Open( this.txtOpen_FilePath.Text);
MSExcel.Worksheet sheet = (MSExcel.Worksheet)book1.Worksheets[1];
MSExcel.Range range = sheet.GetRange("A1", "F13");
object value = range.Value; //the value is boxed two-dimensional array
}
The code is provided from this post. It should be much more efficient than your code, but may not be the best.

how can i calculated values after Worksheet.Calculate()?

i tried Trial version of Gembox.SpreadSheet.
when i Get Cells[,].value by for() or Foreach().
so i think after Calculate() & get Cell[].value, but that way just take same time,too.
it take re-Calculate when i Get Cell[].value.
workSheet.Calcuate(); <- after this, values are Calculated, am i right?
for( int i =0; i <worksheet.GetUsedCellRange(true).LastRowIndex+1;++i)
{
~~~~for Iteration~~~
var value = workSheet.Cells[i,j].Value; <- re-Calcuate value(?)
}
so here is a Question.
Can i Get calculated values? or you guys know pre-Calculate function or Get more Speed?

Unfortunate, I'm not sure what exactly you're asking, can you please try reformulating your question a bit so that it's easier to understand it?
Nevertheless, here is some information which I hope you'll find useful.
To iterate through all cells, you should use one of the following:
1.
foreach (ExcelRow row in workSheet.Rows)
{
foreach (ExcelCell cell in row.AllocatedCells)
{
var value = cell.Value;
// ...
}
}
2.
for (CellRangeEnumerator enumerator = workSheet.Cells.GetReadEnumerator(); enumerator.MoveNext(); )
{
ExcelCell cell = enumerator.Current;
var value = cell.Value;
// ...
}
3.
for (int r = 0, rCount = workSheet.Rows.Count; r < rCount; ++r)
{
for (int c = 0, cCount = workSheet.CalculateMaxUsedColumns(); c < cCount; ++c)
{
var value = workSheet.Cells[r, c].Value;
// ...
}
}
I believe all of them will have pretty much the same performances.
However, depending on the spreadsheet's content this last one could end up a bit slower. This is because it does not exclusively iterate only through allocated cells.
So for instance, let say you have a spreadsheet which has 2 rows. The first row is empty, it has no data, and the second row has 3 cells. Now if you use 1. or 2. approach then you will iterate only through those 3 cells in the second row, but if you use 3. approach then you will iterate through 3 cells in the first row (which previously were not allocated and now they are because we accessed them) and then through 3 cells in the second row.
Now regarding the calculation, note that when you save the file with some Excel application it will save the last calculated formula values in it. In this case you don't have to call Calculate method because you already have the required values in cells.
You should call Calculate method when you need to update, re-calculate the formulas in your spreadsheet, for instance after you have added or modified some cell values.
Last, regarding your question again it is hard to understand it, but nevertheless:
Can i Get calculated values?
Yes, that line of code var value = workSheet.Cells[i,j].Value; should give you the calculated value because you used Calculate method before it. However, if you have formulas that are currently not supported by GemBox.Spreadsheet's calculation engine then it will not be able to calculate the value. You can find a list of currently supported Excel formula functions here.
or you guys know pre-Calculate function or Get more Speed?
I don't know what "pre-Calculate function" means and for speed please refer to first part of this answer.

Using DataGridView in Visual Studio C#

I have a string that contains: "# of rows, # of columns, Row'X'Col'X'=Serial#, ...
How do I create a DataGrid table with the number of rows and columns defined, and then place the serial #s into the grid.
Examples:
2,1,R1C1=111,R2C1=112,
2,2,R1C1=211,R1C2=212,R2C1=213,R2C2=214,
thanks

Below is code that does what you are asking; however I must point out some problems with this approach. First, getting the total rows and cols from the first two elements in order to create your table is risky. If that data is wrong, this code will most likely crash or possibly omit data. Example if the input is: 2,2,RXCX=.., RXCX=.., RXCX=.., RXCX=..,RXCX=, RXCX=… This line will only get the first 4 values.
Worse… this will crash… if the input is 2,2,RXCX=.., RXCX=.. Then it will crash when you try to access the 4th element in the splitArray because there isn’t a 4th element. Either way is not good.
My point is to be safe… it would be a better approach to see how much data is actually there before you create the grid. You could get how many items there are with StringArray.Length minus the first two elements. These elements will define the dimensions and allow you to check their validity. This will make sure your loops won’t go out of bounds because the supplied data was wrong. It seems redundant and error prone to supply the dimension values when you can get that info from the data itself.
I still am not 100% sure what you want to accomplish here. It looks like a search of some form. This is what I am picturing…
Looking at your (previous) screen shots it appears to me that after you type into the Serial # text box and click the “Search Txt Files” button it will search for data that came from the input string i.e. “PLX51…” and then have the grid display the “filtered” results that match (or are LIKE) what’s in the Serial # textbox. If this is true, I would ignore the RXCX vales and put the data in a single column. Then wire up an OnKeyPress event for the text box to filter the grid whenever the user types into the Serial # text box.
Otherwise I am lost as to why you would need to create the data in the fashion described. Just because the input has unnecessary data… doesn’t mean you have to use it. Just a thought.
string inputString = "2,2,R1C1=211,R1C2=212,R2C1=213,R2C2=214";
string[] splitArray = inputString.Split(',');
int totalRows = int.Parse(splitArray[0]);
int totalCols = int.Parse(splitArray[1]);
int itemIndex = 2;
// add the columns
for (int i = 0; i < totalCols; i++)
{
dataGridView1.Columns.Add("Col", "Col");
}
// add the rows
dataGridView1.Rows.Add(totalRows);
for (int i = 0; i < totalRows; i++)
{
for (int j = 0; j < totalCols; j++)
{
dataGridView1.Rows[i].Cells[j].Value = splitArray[itemIndex];
itemIndex++;
}
}

C# how to iterate over excel columns

I want to get a specific column of an excel sheet and then iterate through it's cells. I want it to look something like this:
Excel.Workbook workbook = app.Workbooks.Open(svDropPath);
Excel.Worksheet xlWorkSheet = (Excel.Worksheet)workbook.Sheets["Sheet Name"];
var col = xlWorkSheet.UsedRange.Columns["C:C", Type.Missing]; // I want the 3rd column
foreach(Cell c in col)
....
How do I actually make this foreach loop?

Your loop will looks as follow:
foreach (Excel.Range item in col.Cells)
{
//whatever you want to do with your cells, here- msgbox of cells value
MessageBox.Show(Convert.ToString(item.Value));
}

I believe there is no nice way of doing it other than to loop through the indices in question and use either Cells or Rows:
for (int i = 1; i <= max; i++)
{
Range cell = col.Cells[i, 1];
// or
Range cell = col.Rows[i];
}
However, note that if you are reading and/or writing all the cells, you are much better off reading/writing the whole column to/from an array of object, and then looping through the array items, as outlined in my answer https://stackoverflow.com/a/18058144/1737957 . Not only is this much faster, you can also use nicer language constructs for looping since you are now dealing with a straightforward C# array.
The only reason you would have to loop rather than do this AFAIK is if you were accessing something like conditional formats etc., rather than just cell contents, and you couldn't write a whole range of them in one statement. However there may be ways of doing these too using arrays.

Optimized way of adding multiple hyperlinks in excel file with C#

I wanted to ask if there is some practical way of adding multiple hyperlinks in excel worksheet with C# ..? I want to generate a list of websites and anchor hyperlinks to them, so the user could click such hyperlink and get to that website.
So far I have come with simple nested for statement, which loops through every cell in a given excel range and adds hyperlink to that cell:
for (int i = 0; i < _range.Rows.Count; i++)
{
Microsoft.Office.Interop.Excel.Range row = _range.Rows[i];
for (int j = 0; j < row.Cells.Count; j++)
{
Microsoft.Office.Interop.Excel.Range cell = row.Cells[j];
cell.Hyperlinks.Add(cell, adresses[i, j], _optionalValue, _optionalValue, _optionalValue);
}
}
The code is working as intended, but it is Extremely slow due to thousands of calls of the Hyperlinks.Add method.
One thing that intrigues me is that the method set_Value from Office.Interop.Excel can add thousands of strings with one simple call, but there is no similar method for adding hyperlinks (Hyperlinks.Add can add just one hyperlink).
So my question is, is there some way to optimize adding hyperlinks to excel file in C# when you need to add a large number of hyperlinks...?
Any help would be apreciated.

I am using VS2010 and MS Excel 2010.
I have the very same problems (adding 300 hyperlinks via Range.Hyperlinks.Add takes approx. 2 min).
The runtime issue is because of the many Range-Instances.
Solution:
Use a single range instance and add Hyperlinks with the "=HYPERLINK(target, [friendlyName])" Excel-Formula.
Example:
List<string> urlsList = new List<string>();
urlsList.Add("http://www.gin.de");
// ^^ n times ...
// create shaped array with content
object[,] content = new object [urlsList.Count, 1];
foreach(string url in urlsList)
{
content[i, 1] = string.Format("=HYPERLINK(\"{0}\")", url);
}
// get Range
string rangeDescription = string.Format("A1:A{0}", urlsList.Count+1) // excel indexes start by 1
Xl.Range xlRange = worksheet.Range[rangeDescription, XlTools.missing];
// set value finally
xlRange.Value2 = content;
... takes just 1 sec ...