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Filter with PredicateBuilder
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cgallant View Drop Down
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Joined: 21-Feb-2011
Posts: 1 		Post Options Post Options   Quote cgallant Quote  Post ReplyReply Direct Link To This Post Topic: Filter with PredicateBuilder
    Posted: 21-Feb-2011 at 12:08pm

Hello,

I have been working with my PagedCollectionView by setting its filter which then changes my data grid on my page. The filter is set by changing values in combo boxes on my form.

PagedCollectionView  empListView = new PagedCollectionView(employees);
empListView.Filter = new Predicate<object>(DoFilter);


private bool DoFilter(object o)
{
           Employee emp = o as Employee;
            If (emp != null)
            {
                  if( cboEmployeeState.Text  != “” )
                  {
                                   if( cboEmployeeTitle.Text  != “” )
                                   {
                                                return true;
                                    }
                                    return true;
                   }
                  elseif( cboEmployeeTitle.Text  != “” )
                  {
                       return true;
                   }
                   else
                   {
                       return false;
                    }
            }
            return false;
}


Can i return an answer using the PredicateBuilder that the PageCollectionView can use? I looked in the forums and found this.

Expression<Func<SIGN, bool>> p1, p2, checkP;
if (cboEmployeeState.Text != "")
     p1 = p => p.State.Contains("Ohio");
if (cboEmployeeTitle.Text  != "")
     p2 = p => p.Title.Contains("Manager");
    
checkP = PredicateBuilder.Or(p1, p2);


But i can not figgure out how to make the PageCollectionFilter use this or if even can be done.

Thanks, for any help,
Craig

 
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DenisK View Drop Down
IdeaBlade
IdeaBlade


Joined: 25-Aug-2010
Posts: 715 		Post Options Post Options   Quote DenisK Quote  Post ReplyReply Direct Link To This Post Posted: 21-Feb-2011 at 6:23pm
Hi cgallant;

This is actually pretty tricky and not as straight forward as we would have hoped. Please see the code sample below.

var p1 = PredicateBuilder.Make(typeof(Category), "CategoryName", FilterOperator.Contains, "Produce");
        var predicate = p1.ToPredicate<Category>();
        Func<Category, bool> someFunc = predicate.Compile();
        Predicate<object> filter = t => someFunc((Category)t);

        pcv.Filter = filter;

I was able to find the answer here.


Hope this helps.
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