entity framework - set empty datasource

Question

Hello !

i'm using entity framework , and i have a form with bindingsource , and some bound textboxes ( all bound at design time)

Depending to some option that user select , i need to display all the records , or some of the records  , or no records.

i have a button select , and on Click event i have :

if contitions1 then

Mybindingsource.datasource=From t in context.table1 where .......  some conditions                                            

                                               select t

else

Mybindingsource.datasource=context.table1

end if

Everything is ok when the instruction in else section is executed , or when the From.... Where..... select result non empty.

When From....where.... select  is empty i get an error :

Cannot bind to the property or column xxxxxxx on the DataSource.
Parameter name: dataMember

what can i do ?

Because i need that the textboxes controls on form becomes empty if no records on selection.

thank you.

Answer 1

 Sometimes binding is a crutch that leads a programmer to not know how to

load controls manually. In some cases, it's much easier to load controls

manually instead of trying to bind everything and not have needed

functionality.

 

Answer 2

it's strange , but if i change :

Mybindingsource.datasource=From t in context.table1 where .......  some conditions                                            

                                               select t

to :

Mybindingsource.datasource=(From t in context.table1 where .......  some conditions                                            

                                               select t).Tolist

 

everything is ok when From.... where... select is empty or non empty.