I have this problem when I try to assign selected value using codebehind, even though I already put the code:
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:
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.
in many example i found in the internet it seems doesn’t work in my VS 2008, they code always has blue line under the Null word.
on the pop up they said:
‘Null’ is not declared, ‘Null’ constant is no longer supported; use system.DBNull instead