How to remove whitespaces inside Place Holder

Question

Hi,
There are white spaces which are creating inside of the placeholder.
Please Any one can tell me how to remove them.
I am using the following code but it showing some error like DataItem doesnot find in place holder


<asp:PlaceHolder runat="server" Id="div place holder"Visible='<%# ((string)Container.DataItem).Trim().Length > 0 %>'>