Filter dynamically

Radzen Blazor Studio
1

Hello,

what is the best way to build the Filter string dynamically because we have a lot of parameters?
(only to concatenate the strings?)

here is only a query with one parameter "search":

        pfuschertyps = await PDBService.GetPfuschertyps(new Query { Filter = $@"i => i.Pfuschertyp1.Contains(@0)", FilterParameters = new object[] { search } });

robert

2

You can append to this expression. For example:

$@"i => i.Pfuschertyp1.Contains(@0) || i.SomeOtherProp.Contains(@0)"

If you pass additional parameter you can use the parameter index:

pfuschertyps = await PDBService.GetPfuschertyps(new Query { Filter = $@"i => i.Pfuschertyp1.Contains(@0) || i.SomeOtherProp.Contains(@1)", FilterParameters = new object[] { search, someOtherParameter } });
3

I know that but I want to buld the expression dynamically because some parameters sould only added if they are not null...

4

Since you already know how the Query is constructed you can do it programmatically as well.

5

OK that means there is no better way to buld the Query.Filter string as concatenate the strings- right?
((I'm not so familiar with Entity Framework)

robert

6

This API is related to Radzen.Blazor only built on the top of Dynamic LINQ expressions. There is no default high level EF API that allows building dynamically Where().