generating Excel files w/ .NET? (an ASP.NET, C# web app)

[matt]

hello,

can anyone speak to some of the common or preferred methods for
building Excel .XLS files, programmatically thru the .NET framework?

i have an intranet app that needs to generate & email .xls files for
users. these are not reports, but rather more like forms. its a pretty
simple doc, two worksheets -- the first is basic info common to all
recepients. the second is a simple data table that, depending on the
recepient, contains pre-populated rows of data. there are some blank
date fields in the table for the recepient to fill in. (and yep, after
they do so and save, it will eventually get sent back to us for parsing
of the values)

i wont really get into the why's of this project, but suffice it to say
this is the workflow we need.

i had hoped i could retrieve an ADO.NET datatable of my recepient's
rows, loop thru it, and add rows/cells to an in-memory Excel doc. then
stream it out to the user or email it.

as i understand VBA was designed to do this, but i would prefer to
avoid VBA and keep it all .NET. ive found some 3rd party components to
do such a thing, but at $7,500 a CPU, they seem pretty expensive. are
there any other alternatives?


thanks!
matt

 

[Guest]

You can use the Excel COM wrapper, but I've found it quite easy to write
Excel-XML to a file (then you don't even need Excel installed on your
server). If you name that file with an .xls extension, when you double-click
on it, it brings up Excel and gets interpreted just fine.

The trick is to build a real Excel spreadsheet the way you want then save it
as XML to see what tricks are involved in using the XML. Then just do that
in code. I just recently did this to create a spreadsheet with 3 tabs,
auto-wrapped cells,
data filters, inter-tab hyperlinks, cell highlighting, and freeze-panes.
It's all right there in the XML, you just do what they do.

Here's a good starter article:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnexcl2k2/html/odc_xmlss.asp

 

[q]

I just copy pasted from a project I did last year... Given a
dataTable, it creates the XLS and all that and returns the file name
(there was a segment of the code the generated a file name, but I
deleted that). This works great for everything we need... Basically,
you just create a table and start putting stuff in the table. That
said, there are some seriously anal details it wants.

public static string CreateExcelReport(DataTable dataTable) {
string tempFolder =
System.Configuration.ConfigurationManager.AppSettings["TempFolder"];
if (tempFolder.Length < 1) {
throw new IapException("TempFolder was not specified in
configuration file.");
}
string excelString = @"Provider=Microsoft.Jet.OLEDB.4.0;
Data Source=" + tempFolder;
string statements = "";

string excelFileName = "MyFileName.xls";
excelString += excelFileName;
excelString += "; Extended Properties=Excel 8.0";

string current = DateTime.Now.ToString("D").Replace(" ",
"").Replace(",", "");

List<string> columns = new List<string>( );
foreach (DataColumn dc in dataTable.Columns) {
columns.Add(dc.ColumnName);
}

bool first = true;
using (OleDbConnection connection = new
OleDbConnection(excelString)) {
connection.Open( );

OleDbCommand cmd = new OleDbCommand( );
cmd.Connection = connection;

string createStatement = "create table Report" +
current + " (";
foreach (string column in columns) {
if (!first) {
createStatement += ", ";
}
string column2 = column.Replace("-", "");
createStatement += "[" + column2 + "]
VarChar(200)";
first = false;
}

createStatement += ");";

statements += createStatement + "\n";
cmd.CommandText = createStatement;
cmd.ExecuteNonQuery( );
}

using (OleDbConnection connection = new
OleDbConnection(excelString)) {
DataTable dt = new DataTable("ExcelTable");
OleDbDataAdapter da = new OleDbDataAdapter( );

string insertStatement = "insert into [Report" + current + "] (";

first = true;
foreach (string column in columns) {
if (!first) {
insertStatement += ", ";
}
string column2 = column.Replace("-", "");
insertStatement += "[" + column2 + "]";
first = false;
}

insertStatement += ") values (";

first = true;
foreach (string column in columns) {
if (!first) {
insertStatement += ", ";
}
string column2 = column.Replace("-", "");
insertStatement += "@" + column2.Replace(" ", "");
first = false;
}

insertStatement += ");";

statements += insertStatement + "\n";

da.InsertCommand = new OleDbCommand(insertStatement,
connection);

foreach (string column in columns) {
string column2 = column.Replace("-", "");
da.InsertCommand.Parameters.Add("@" +
column.Replace(" ", ""), OleDbType.VarChar).SourceColumn = column2;
}

foreach (string column in columns) {
string column2 = column.Replace("-", "");
dt.Columns.Add(column2,
Type.GetType("System.String"));
}

int n = 0;
foreach (DataRow row in dataTable.Rows) {
DataRow excelRow = dt.NewRow( );
foreach (string column in columns) {
excelRow[column.Replace("-", "")] =
row[column];
}

dt.Rows.Add(excelRow);
}

da.Update(dt);

return excelFileName;
}
}

 

[Steve C. Orr [MVP, MCSD]]

There are a variety of ways to export to excel, and most of them are
outlined in this article:
http://SteveOrr.net/Articles/ExcelExport.aspx

Here's another option:
http://SteveOrr.net/Articles/ExportPanel.aspx

And here are a few good 3rd party options that make it easy to do complex
things.
http://SteveOrr.net/reviews/AsposeExcel.aspx
http://officewriter.softartisans.com/officewriter-37.aspx
http://www.syncfusion.com/products/xlsio/

 

[Stephane Rodriguez]

"$7,500 a CPU, they seem pretty expensive"

Indeed expensive.

xlsgen : http://xlsgen.arstdesign.com

 

[NickHK]

VB/VBA is COM based. .Net is not.
You would need a COM wrapper for any .Net components and call the wrapper
from Excel/VBA.

But why not use the standard ADO library from VBA and avoid the .Net
completely.
Also the email side is striaght forward :
http://www.rondebruin.nl/sendmail.htm

If you want to "keep it all .NET", you can't use VBA.

NickHK

 

[Nicolas Guinet]

The MicrosoftExcelClient is a simple class any developer can use in their
codes to interface to Excel Documents.
It has been created in C#.NET and uses OleDb.

http://www.codeproject.com/useritems/microsoftexcelclient.asp

I use it with success

Regards
Nicolas Guinet

 

[matt]

thanks all for the replies.

i am not interested in merely exporting data to excel, thats easy. but
rather in designing mid-complexity documents, some of which is based on
dynamic data.

i will investigate your suggested links.


thanks!
matt

 

[matt]

The trick is to build a real Excel spreadsheet the way you want then save it
as XML to see what tricks are involved in using the XML. Then just do that
in code.

thanks tim!

that sounds really sweet. however, i didnt see "XML Spreadsheet" as a
"Save As..." option. then i realized we're on Excel 2000, and it
appears the xml format was introduced in Excell 2002. doh.

looks like i cant do that then, huh?


matt