Monday, May 30, 2011

ASP.NET Export GridView to Excel

Many times there is requirement to export the data from Gridview to Excel or PDF. Here I am going to discuss export to excel. When initially this was the requirement I thought there will be ready to use code snippet MSDN perhaps I couldn’t find that. After searching other sites I settled on following approach.
Here along with exporting gridview data I also wanted to add some additional information say report name and report generation date. Also there are controls in gridview which I need to handle while exporting it.
Basically I have created two functions one for export and other for handling the controls in the Gridview cells.

public static void Export(string fileName, GridView gv,string ReportName,DateTime ExportDate )
    {
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.AddHeader(
            "content-disposition", string.Format("attachment; filename={0}", fileName));
        HttpContext.Current.Response.ContentType = "application/ms-excel";
        using (StringWriter sw = new StringWriter())
        {
            using (HtmlTextWriter htw = new HtmlTextWriter(sw))
            {
                //  Create a table to contain the grid
                Table table = new Table();
                TableRow HeaderRow = new TableRow();
                TableRow HeaderRow1 = new TableRow();
                TableCell cell = new TableCell();
                TableCell cell1 = new TableCell();
                TableCell cell2 = new TableCell();
                TableCell cell3 = new TableCell();
                //  include the gridline settings
                table.GridLines = gv.GridLines;
                cell.Text = "Report Name";
                cell1.Text = ReportName;
                cell2.Text = "Date:";
                cell3.Text =Convert.ToString( ExportDate);
                cell.ColumnSpan = gv.HeaderRow.Cells.Count - 2;
               
                cell2.ColumnSpan = gv.HeaderRow.Cells.Count - 2;
                HeaderRow.Cells.Add(cell);
                HeaderRow.Cells.Add(cell1);
                HeaderRow1.Cells.Add(cell2);
                HeaderRow1.Cells.Add(cell3);
                table.Rows.Add(HeaderRow);
                table.Rows.Add(HeaderRow1);
                cell3.HorizontalAlign = HorizontalAlign.Left;
                cell2.HorizontalAlign = HorizontalAlign.Right;
                cell.HorizontalAlign = HorizontalAlign.Right;
                cell.Font.Bold = true;
                cell2.Font.Bold = true;
                cell.Font.Size = FontUnit.Small;
                cell2.Font.Size = FontUnit.Small;
    //SET CELL BACKGROUND
                foreach (TableCell tc in gv.HeaderRow.Cells)
                    tc.BackColor = System.Drawing.Color.FromArgb(197, 217, 241);
                //  add the header row to the table
                if (gv.HeaderRow != null)
                {
                    PrepareControlForExport(gv.HeaderRow);
                    table.Rows.Add(gv.HeaderRow);
                }

                //  add each of the data rows to the table
                foreach (GridViewRow row in gv.Rows)
                {

                   PrepareControlForExport(row);
                    row.VerticalAlign = VerticalAlign.Top;
                    table.Rows.Add(row);
                }

                //  add the footer row to the table
                if (gv.FooterRow != null)
                {
                    PrepareControlForExport(gv.FooterRow);
                    table.Rows.Add(gv.FooterRow);
                }

                //  render the table into the htmlwriter
                table.RenderControl(htw);

                //  render the htmlwriter into the response
                HttpContext.Current.Response.Write(sw.ToString());
                HttpContext.Current.Response.End();
            }
        }
    }


private static void PrepareControlForExport(Control control)
    {
        for (int i = 0; i < control.Controls.Count; i++)
        {
            Control current = control.Controls[i];
            if (current is LinkButton)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as LinkButton).Text));
            }
            else if (current is ImageButton)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as ImageButton).AlternateText));
            }
            else if (current is HyperLink)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as HyperLink).Text));
            }
            else if (current is DropDownList)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as DropDownList).SelectedItem.Text));
            }
            else if (current is CheckBox)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as CheckBox).Checked ? "True" : "False"));
            }

            if (current.HasControls())
            {
               PrepareControlForExport(current);
            }
        }
    }