Formatting Currency in a GridView

To format data in a gridview boundcolumn or Eval statement using the property of the boundcolumn called DataFormatString or include the format in the Eval statement like this: [I added an extra space between the brackets so this would format correctly]
< %# Server.HtmlEncode( Eval("InvoiceAmount", "{0:$#,#.#0}").ToString() ) % >"

I got this from a great article http://blog.stevex.net/string-formatting-in-csharp/

Using the decimal value 4219.60 as my number from the database for a product.

{0}
4219.60

{0:c}
$4,219.60

{0:c2}
$4,219.60

{0:c4}
$4,219.6000

{0:$#.#}
$4219.6

{0:$#,#.#}
$4,219.6

{0:#,#.##}
$4,219.6

{0:$#,#.#0}
$4,219.60

The Value of Datakeys in GridView RowDataBound

To find the value of your gridview attribute Datakeys use this C# code

protected void gvSummary_RowDataBound(object sender, GridViewRowEventArgs e)

{
   DataTable dt = new DataTable();
   if (e.Row.RowType == DataControlRowType.DataRow)
   {
      //find the invoice number - which is the Datakeys
      int inv = Convert.ToInt32(((GridView)sender).DataKeys[e.Row.RowIndex].Value);

    //find the charges grid - populated based on the invoice number
    GridView gvCh = (GridView)e.Row.FindControl("gvCharges");

    dt = maData.TrapRetrievalInvoiceChargesGet(inv);
    //populate a nested grid
    gvCh.DataSource = dt;
    gvCh.DataBind();

  }
}


ASP Code
asp:GridView ID="gvSummary" runat="server" DataKeyNames="Invoice"

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