DataTable to excel conversion - excel

Question

I have a datagrid which populates a datatable, I want to export the DataTable to excel on click of a button. I am using MVVM for this application. So is it ok to implement the export feature in my view?
Secondly, as i am using xaml and desktop application, how do i capture the grid and its details.
Can any one suggest me some pointers? I am new to this.
Thanks,
Sagar

Answer 1

This is what i have done and it helped me:
private readonly ICommand m_ExportButtonClick;
private string ExcelFilePath = "";
public ICommand ExportButtonClick { get { return m_ExportButtonClick; } }
private void OnRunExport()
{
try
{
if (queryDatatable == null || queryDatatable.Columns.Count == 0)
throw new Exception("ExportToExcel: Null or empty input table!\n");
// load excel, and create a new workbook
Excell.Application excelApp = new Excell.Application();
excelApp.Workbooks.Add();
// single worksheet
Excell._Worksheet workSheet = excelApp.ActiveSheet;
// column headings
for (int i = 0; i < queryDatatable.Columns.Count; i++)
{
workSheet.Cells[1, (i + 1)] = queryDatatable.Columns[i].ColumnName;
}
// rows
for (int i = 0; i < queryDatatable.Rows.Count; i++)
{
// to do: format datetime values before printing
for (int j = 0; j < queryDatatable.Columns.Count; j++)
{
workSheet.Cells[(i + 2), (j + 1)] = queryDatatable.Rows[i][j];
}
}
// check fielpath
if (ExcelFilePath != null && ExcelFilePath != "")
{
try
{
workSheet.SaveAs(ExcelFilePath);
excelApp.Quit();
MessageBox.Show("Excel file saved!");
}
catch (Exception ex)
{
throw new Exception("ExportToExcel: Excel file could not be saved! Check filepath.\n"
+ ex.Message);
}
}
else // no filepath is given, the file opens up and the user can save it accordingly.
{
excelApp.Visible = true;
}
}
catch (Exception ex)
{
MessageBox.Show("There is no data to export. Please check your query/ Contact administrator." + ex.Message);
}
}
#endregion

Answer 2

Here's an extension method to output to any DataTable to a csv (which excel can open)
Imports System.Text
Imports System.IO
Imports System.Runtime.CompilerServices
Module ExtensionMethods
<Extension()> _
Public Sub OutputAsCSV(ByVal dt As DataTable, ByVal filePath As String)
Dim sb As New StringBuilder()
'write column names to string builder
Dim columnNames As String() = (From col As DataColumn In dt.Columns Select col.ColumnName).ToArray
sb.AppendLine(String.Join(",", columnNames))
'write cell value in each row to string builder
For Each row As DataRow In dt.Rows
Dim fields As String() = (From cell In row.ItemArray Select CStr(cell)).ToArray
sb.AppendLine(String.Join(",", fields))
Next
'write string builder to file
File.WriteAllText(filePath, sb.ToString())
End Sub
End Module

Answer 3

Try googling around a little. This is a very common problem and has been asked a lot already. Here's a good answer from this SO question
public static void ExportToExcel<T>(IEnumerable<T> exportData)
{
Excel.ApplicationClass excel = new Excel.ApplicationClass();
Excel.Workbook workbook = excel.Application.Workbooks.Add(true);
PropertyInfo[] pInfos = typeof(T).GetProperties();
if (pInfos != null && pInfos.Count() > 0)
{
int iCol = 0;
int iRow = 0;
foreach (PropertyInfo eachPInfo in pInfos.Where(W => W.CanRead == true))
{
// Add column headings...
iCol++;
excel.Cells[1, iCol] = eachPInfo.Name;
}
foreach (T item in exportData)
{
iRow++;
// add each row's cell data...
iCol = 0;
foreach (PropertyInfo eachPInfo in pInfos.Where(W => W.CanRead == true))
{
iCol++;
excel.Cells[iRow + 1, iCol] = eachPInfo.GetValue(item, null);
}
}
// Global missing reference for objects we are not defining...
object missing = System.Reflection.Missing.Value;
// If wanting to Save the workbook...
string filePath = System.IO.Path.GetTempPath() + DateTime.Now.Ticks.ToString() + ".xlsm";
workbook.SaveAs(filePath, Excel.XlFileFormat.xlOpenXMLWorkbookMacroEnabled, missing, missing, false, false, Excel.XlSaveAsAccessMode.xlNoChange, missing, missing, missing, missing, missing);
// If wanting to make Excel visible and activate the worksheet...
excel.Visible = true;
Excel.Worksheet worksheet = (Excel.Worksheet)excel.ActiveSheet;
excel.Rows.EntireRow.AutoFit();
excel.Columns.EntireColumn.AutoFit();
((Excel._Worksheet)worksheet).Activate();
}
}