asp.net - Always show FooterTemplate, even no data

Question

Is there a short way to make a FooterTemplate (in a GridView) always visible, even when DataSource is empty?

Answer 1

I was having trouble with this as well. The link from Alconja helps a lot (Thanks Alconja) but GridView.FooterRow then returns null. I need it for inserting new records from the footer.

This is my final solution that works. Now you can insert data from the footer even if the grid is empty.

GridViewExtended.cs (a class in the App_Code folder):

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace YourNamespace
{

  public class GridViewExtended : GridView
  {
    #region Public Properties
    [Category("Behavior")]
    [Themeable(true)]
    [Bindable(BindableSupport.No)]
    public bool ShowFooterWhenEmpty
    {
      get
      {
        if (this.ViewState["ShowFooterWhenEmpty"] == null)
        {
          this.ViewState["ShowFooterWhenEmpty"] = false;
        }

        return (bool)this.ViewState["ShowFooterWhenEmpty"];
      }
      set
      {
        this.ViewState["ShowFooterWhenEmpty"] = value;
      }
    }
    #endregion

    private GridViewRow _footerRow2;
    public override GridViewRow FooterRow
    {
      get
      {
        GridViewRow f = base.FooterRow;
        if (f != null)
          return f;
        else
          return _footerRow2;
      }
    }

    protected override int CreateChildControls(System.Collections.IEnumerable dataSource, bool dataBinding)
    {
      int rows = base.CreateChildControls(dataSource, dataBinding);

      //  no data rows created, create empty table if enabled
      if (rows == 0 && (this.ShowFooterWhenEmpty))
      {
        //  create the table
        Table table = this.CreateChildTable();

        DataControlField[] fields;
        if (this.AutoGenerateColumns)
        {
          PagedDataSource source = new PagedDataSource();
          source.DataSource = dataSource;

          System.Collections.ICollection autoGeneratedColumns = this.CreateColumns(source, true);
          fields = new DataControlField[autoGeneratedColumns.Count];
          autoGeneratedColumns.CopyTo(fields, 0);
        }
        else
        {
          fields = new DataControlField[this.Columns.Count];
          this.Columns.CopyTo(fields, 0);
        }

        if (this.ShowHeaderWhenEmpty)
        {
          //  create a new header row
          GridViewRow headerRow = base.CreateRow(-1, -1, DataControlRowType.Header, DataControlRowState.Normal);
          this.InitializeRow(headerRow, fields);

          //  add the header row to the table
          table.Rows.Add(headerRow);
        }

        //  create the empty row
        GridViewRow emptyRow = new GridViewRow(-1, -1, DataControlRowType.EmptyDataRow, DataControlRowState.Normal);
        TableCell cell = new TableCell();
        cell.ColumnSpan = fields.Length;
        cell.Width = Unit.Percentage(100);

        //  respect the precedence order if both EmptyDataTemplate
        //  and EmptyDataText are both supplied ...
        if (this.EmptyDataTemplate != null)
        {
          this.EmptyDataTemplate.InstantiateIn(cell);
        }
        else if (!string.IsNullOrEmpty(this.EmptyDataText))
        {
          cell.Controls.Add(new LiteralControl(EmptyDataText));
        }

        emptyRow.Cells.Add(cell);
        table.Rows.Add(emptyRow);

        if (this.ShowFooterWhenEmpty)
        {
          //  create footer row
          _footerRow2 = base.CreateRow(-1, -1, DataControlRowType.Footer, DataControlRowState.Normal);
          this.InitializeRow(_footerRow2, fields);

          //  add the footer to the table
          table.Rows.Add(_footerRow2);
        }

        this.Controls.Clear();
        this.Controls.Add(table);
      }

      return rows;
    }
  }

}

In the aspx page, simply add

<%@ Register TagPrefix="YourPrefix" Namespace="YourNamespace" %>

and replace <asp:GridView with <YourPrefix:GridViewExtended

Hope it helps someone.