Export SharePoint list to excel using DataGrid

From time to time I learn that the OOTB export to excel capabilities of SharePoint are missing some edge.

For instance - the latest thing my colleague found is that if you do not have excel 2007 but earlier versions, it does not export some column types correctly, or are completely missing.

So, I have created a simple ASP.NET web part that will allow the user to export the list items / list view into excel, that does not require a specific version of excel to be installed on the client.

The concept is simple:
Connect to a list / view,
Get items as DataTable
Connect DataTable to a DataGrid
Export DataGrid to excel.

So, to get the list items / view items into a Data Table, I used one of these code samples:

For list URL + view ID:

using (SPSite site = new SPSite(txtListUrl.Text))
{
  using (SPWeb web = site.OpenWeb())
  {
    SPList list = web.GetListFromUrl(txtListUrl.Text);
    DataTable items = list.GetItems(list.Views[new Guid(cmbListView.SelectedValue)]).GetDataTable();

    ExportToExcel(items);
  }
}

Or, if you plan to place the WP in the list view page - here it is working with the SPContext.Current.List:

SPList list = SPContext.Current.List;
DataTable items = list.Items.GetDataTable();

ExportToExcel(items);

Ok, so now we have the DataTable, all we have to do is implement the code that will export the DataTable to excel using Data Grid:

private void ExportToExcel(DataTable items)
{
  theGrid = new DataGrid();
  theGrid.DataSource = items;
  theGrid.DataBind();

  Page.Response.Clear();
  Page.Response.ContentType = "application/vnd.ms-excel";
  Page.Response.Charset = "utf-8";
  Page.Response.AddHeader("Content-Disposition", "attachment;filename="+DateTime.Now.ToString("yyyyMMdd_hhmmss")+".xls");

  System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
  System.Web.UI.HtmlTextWriter oHtmlTextWriter = new   System.Web.UI.HtmlTextWriter(oStringWriter);
  theGrid.RenderControl(oHtmlTextWriter);

  Page.Response.Write(oStringWriter.ToString());
  Page.Response.End();
}

And guess what? It is that simple!

Enjoy,

Shai Petel
KWizCom VP Professional Services

UTF-8 with signature?

Few days ago I was at my customer and we witnessed a wired behavior of excel.

We wanted to display data in excel from the web, so that when you click a link excel will open and display some data in it (not within explorer).

Doing this is pretty simple, all we have to do is create a data grid control, bind it to a data source and let it render.

When we want it to open to excel we have to replace the "pre-render" method with this simple code:
Page.Response.Clear();//clear other HTML form response
Page.Response.AddHeader("Content-Disposition", "attachment;filename=StudentsList.xls");//to open in excel
Page.Response.Charset = "65001";//for UTF-8
myDG.RenderControl(writer);//render grid HTML
Page.Response.End();//End response here.

This works great for most cases.

My client had to display some non-English characters that were all UTF8 encoded. When saving the result HMTL in notepad using UTF8 excel was able to display the special chars ok, but when using the code sample above - we got some wrong data.

After googling around for a while i managed to understand that excel must use UTF8 with signature text and i had to add a signature to it.

So - how do I signature my file as UTF8???

Some more googling allowed me to learn that all I needed to do is add these bytes to the start of the file:
0xEF, 0xBB, 0xBF

Using C#, here is the complete and correct way to do this:

Page.Response.Clear();
Page.Response.ContentType = "application/vnd.ms-excel";
Page.Response.AddHeader("Content-Disposition", "attachment;filename=StudentsList.xls");
Page.Response.Charset = "65001";
byte[] b = new byte[] { 0xEF, 0xBB, 0xBF };
Page.Response.BinaryWrite(b);
myDG.RenderControl(writer);
Page.Response.End();

Now everything should be rendered okay and my file is saved with UTF8 with signature!!!

Hooray!

Well, hope this helps, since I didn't manage to find any document that explains this I thought it might help if I publish one...

Peace, Shai.