clearing dropdownlist selected value

I have this problem when I try to assign selected value using codebehind, even though I already put the code:

dropdownlist.selectedindex=null
or dropdownlist.selectedindex=-1
or dropdownlist.selectedindex=""

all throw error said it can’t have duplicate selected value.
now there are two way to clear the selected value, first by do it twice, like what is listed in bug section in Q327244 (http://support.microsoft.com/default.aspx?scid=kb;en-us;327244), like this:

dropdownlist.selectedvalue=-1 ‘this will change the selected value index to index number 0
dropdownlist.selectedvalue=-1 ‘this will clear all selected item

or add this code:

dropdownlist.ClearSelection()

setting crystal report using sqldatasource in visual studio 2008

It’s been several days I looking for connecting crystal report express for visual studio 2008 using sqldatasource, so i can edit the sql query using code behind on runtime. All I found on the net are using dataset or xsd, so more coding required 🙂
But finally I found it in microsoft site, with a few simple steps:
– Create crystal report file.
– Connect to database and add fields on the report, customize it as you like.
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