formatting data in a gridview that's auto generating columns

What a long title! Anyway formatting the cell's onrowdatabound is quite well documented but all of the discussion tends to assume that you'll have specified columns, so you'll have BoundColumns and TemplateItems to work with. But I wanted to use short dates in a gridview where I was letting the gridview auto generate the columns (the default unless you set it to false in the gridview properties).

I only found this little reference to it - you need to scroll down to find the relevant code sample underneath Community Content (http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.autogeneratecolumns%28VS.80%29.aspx). I used a free code converter change it to C# but that code still needed work. The original converted code with original comments, and then mine added in below. This code is easily customized for a wide range of formatting output when your gridview is automatically generating columns.

        protected void Gridview1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            //use syntax to hide baddates
            //maybe also do short date strings?

            //http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.autogeneratecolumns%28VS.80%29.aspx
            // Routine to display an unknown DateTime column
            // as a short date at runtime
            // By Ken Cox [Microsoft MVP]
            // July 28/06
            //
            // Make sure this is a datarow being bound
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                // Create variables to hold values
                DataRowView dtview = default(System.Data.DataRowView);
                int intCounter = 0;
                // Get the contents of the current row
                // as a DataRowView
                dtview = (DataRowView)e.Row.DataItem;
                // Loop through the individual values in the
                // DataRowView's ItemArray
                for (intCounter = 0; intCounter <= dtview.Row.ItemArray.Length - 1; intCounter++)
                {
                    // Check if the current value (item - Layla) is
                    // a System.DateTime type
                    if (dtview.Row[intCounter].GetType() == typeof(DateTime))
                    {
                        // If it is a DateTime, cast it as such
                        // into the variable

                        //Layla: cast item to DateTime 
                        DateTime myNewDate = Convert.ToDateTime(dtview.Row[intCounter]);
                        //now test if that date is missing date, then hide it if so
                        if (myNewDate == myConstants.NOTCOMPLETE_DATETIME)
                        {
                            e.Row.Cells[intCounter].Text = "";
                        }
                        else
                        {
                            // Set the text of the current cell
                            // as the short date representation
                            // of the datetime
                            e.Row.Cells[intCounter].Text = myNewDate.ToShortDateString();
                        }
                    }
                }
            }
        }

If you compare the original code you can see some small differences. Rather than create a DateTime variable holder to place the item into, I just create the variable IF NEEDED (if the item in the row being evaluated is of type DateTime) and populate it with the item cast as a DateTime. Very small, but I prefer that because I think it's easier to read/understand.

If anyone knows of any other ways to accomplish this - namely iterating through the items in a gridview row onrowdatabound, I'd love to compare it, so tell me about it in the comments!

programatically change gridview row background color

//change bgcolor of gridview row based on data
//in this case the data I am testing is in a templatefield that is hidden
//if the data had been added in the last hour, then I apply a certain css class

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DateTime entryDate = Convert.ToDateTime(((DataRowView)e.Row.DataItem)["DtEnter"]);
                DateTime nowDate = DateTime.Now;
                TimeSpan ts = nowDate.Subtract(entryDate);
                
                if (ts.TotalMinutes <= 60)
                {
                    e.Row.CssClass = "updatedRow";
                }
            }
        }

Helper Functions for gridview

I added a class for helper funtions to format gridview output, that can be called from the gridview in the aspx page like so:

Amount:
< % # DCToolbox.DCReports.GridviewHelpers.FormatShort(Eval("grantStartDate")) %>

FormatShort, for example, takes the object and if it's not a dbnull then it converts it to a short and displays that value, as long as the short is not one of the missing value constants for short in the DCConstants class.

There are only a couple of functions in there so far, please feel free to add more. I didn't find anything like this in the toolbox, but I didn't look hard so please let me know if it's redundant.