Custom datatable with metadata used for binding to a Gridview?

Question

I'm binding a datatable to a gridview control, and when I format each column I need to format the data based on whether that column has a particular custom attribute. In this case, a column can represent:

• a text box (in which case I just display the text from the textbox in the gridview),
• a checkbox (in which case I display "Checked" or "Unchecked" based on whether the column's underlying data value is 1 or 0),
• a radio button (in which case I display "On" or "Off" based on whether the column's underlying data value is 1 or 0).

The problem is that the column data types are all strings in the untyped data table being bound to the grid, currently. And the binding uses autoGenerateColumns. So:

1. How do I flag a column as being either a radio, a textbox, or a checkbox?
2. How do I access that "flag" while binding to the grid to show the text, "Checked/Unchecked", or "On/Off"?

I hope I asked this right. Phew!

Answer 1

The best way to do this is to turn off the autogeneration of columns, and then replace the BoundFields for the columns you care about with TemplateFields. There is a tutorial on ASP.NET that can fill in more of the details.

Answer 2

I'm okay with templatefields; what I don't know is how to add metadata to my datatable columns that I can read during GridView databinding. E.g. when I'm binding to a column that has checkbox data, I want to put the word "Checked" or "Unchecked" in the column, but I need to somehow annotate my data table so it contains the column data type.

Answer 3

Okay- I added extended properties to the DataTable columns with the proper data type and checked them on the GridView's RowDataBound event in a loop from 1..numColumns:

myProperty=e.Row.DataItem.dataview.table.columns(i).extendedproperties("TYPE")

and set the value (e.Row.Cells(i).Text) based on the type.