Can't sort on my data column

[Tab Alleman]

I am creating a RadGrid and initially assigning the sortExpression to use the data column, "Plcmt Date" as its FieldName:

 

<SortExpressions>

 

 

<telerik:GridSortExpression FieldName="Plcmt Date" SortOrder="Ascending" />

 

 

</SortExpressions>

 

the column seems to be set up correctly:
 

 

 

<telerik:GridBoundColumn HeaderText="Plcmt Date" UniqueName="PlacementDate" HeaderTooltip=""

 

 

SortDescImageUrl="../RadControls/Grid/Skins/Default/SortDesc.gif" SortAscImageUrl="../RadControls/Grid/Skins/Default/SortAsc.gif"

 

 

DataField="Plcmt Date" SortExpression="Plcmt Date" AllowSorting="true" FooterText="Grand Total">

 

 

 

but I am getting this error:

Error serializing value 'Plcmt Date ASC' of type 'Telerik.Web.UI.GridSortExpression.'

Is it because there is a space in the column name or something?   I've looked all over the site and don't see anything about restrictions on column names that can be used for sorting.

[Tab Alleman]

Never mind.   the error was because I was trying to save the Sort Expression in ViewState and you can't do that without making it serializable.