Cannot compute Count for a data source that does not implement ICollection.

[nxliu]

I have some code like:

XmlNodeList locationNode = xmlDocument.SelectNodes("xpath string");

PagedDataSource pg = new PagedDataSource();
pg.DataSource = locationNode;
pg.AllowPaging = true;
pg.PageSize = 10;
pg.CurrentPageIndex = 0;
DataList1.DataSource = pg;
DataList1.DataBind();

when I run the program, it throws exception on line DataList1.DataBind():

Exception Details: System.Web.HttpException: Cannot compute Count for a data
source that does not implement ICollection.

Source Error:

Line 114: pg.CurrentPageIndex = 0;
Line 115: DataList1.DataSource = pg;
Line 116: DataList1.DataBind();
Line 117: }
Line 118:


since the XmlNodeList implements IEnumerable, I really can't find where the
problem is.
please help? Thanks in advance!

 

[Ben Lovell]

Hi,

The error message in this case is fairly self-explanatory! The XmlNodeList
type does in fact support IEnumerable but not the required ICollection
interface. Internally the PagedDataSource type attempts to use the Count
property exposed on the ICollection interface, if it cannot resolve the page
count it throws the exception you are getting.