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Creating an Excel report with C# using a MySql data source

This blog article will share how to create a multi-worksheet Excel workbook file using C# that fetches report data from a MySql data source.

First, create a Visual Studio C# project and install the EPPlus and MySql.Data Nuget packages.

Next, get yourself a MySqlConnection object connected to your MySql server. If you have a specific database, you'll want to add that to your connection string. My case didn't need to do that. Obviously, change your user, password, and server values to whatever makes sense for your environment. 

                string connstring = string.Format("Server={0}; UID={1}; password={2};default command timeout={3};", serverName, userName, Password, commandTimeout);
                MySqlConnection connection = new MySqlConnection(connstring);

Next, you set up an ExcelPackage object and create worksheets as the code below shows. Notice how the column headers are set and styled.

Then, I fetch my Sql query from a helper class and execute that using a MySqlCommand. The results of my query are fetched using the data reader. As it iterates through the data reader, the code sets the query result values in to specific Excel cell locations using the row and column index values.

                string eppOutput = @"C:\myEppOutput.xlsx";
                FileInfo fi = new FileInfo(eppOutput);
                using (ExcelPackage package = new ExcelPackage(fi))
                    // I two queries that run. Results are put on separate worksheets.
                    for (int queryIdx = 1; queryIdx <= 2; queryIdx++)
                        string worksheetName = "Worksheet" + queryIdx;
                        ExcelWorksheet ws = package.Workbook.Worksheets.Add(worksheetName);
                        // Each page has this four column headers:
                        // Set worksheet's column headers
                        ws.Cells["A1"].Value = "ColumnA";
                        ws.Cells["B1"].Value = "ColumnB";
                        ws.Cells["C1"].Value = "ColumnC";
                        ws.Cells["D1"].Value = "ColumnD";
                        // Make column headers bold
                        ws.Cells["A1:D1"].Style.Font.Bold = true;
                        query = Utils.GetDatabaseQueryString(queryIdx);
                        cmd = new MySqlCommand(query, dbCon.Connection);
                        int row = 2;
                        int col = 1;
                        using (var dataReader = cmd.ExecuteReader())
                            while (dataReader.Read())
                                col = 1;
                                ws.SetValue(row, col++, dataReader.GetString(0));
// Column B and C are always integer values:
                                ws.SetValue(row, col++, int.Parse(dataReader.GetString(1)));
                                ws.SetValue(row, col++, int.Parse(dataReader.GetString(2)));
                                ws.SetValue(row, col++, dataReader.GetString(3));

Note that the col index resets each pass through the dataReader.Read, and the row index resets each time I create a new worksheet.

Finally, we can call package.Save to write out my ExcelPackage object to a file specified in the argument string that we passed to its constructor.