c# - How can i cast IQueryable<> query to IQueryable<obj.getType()>? -

how can factorize code? filter returns several type of document. difficult have query per type... generic method return correct query

thanks

        if(this.comboboxtype.text.equals("vente"))         {             iqueryable<vente> queryv = contextedao.contextedonnees.vente                .include("client")                .include("paiement")                .include("employe").orderby(v => v.venteid);              if (this.tbxnomcli.text != "")                 queryv = queryv.where(v => v.client.nom.contains(this.tbxnomcli.text));             if (this.comboboxetat.text != "tous")                 queryv = queryv.where(v => v.etat == this.comboboxetat.text);             if (this.checkboxdate.checked)                 queryv = queryv.where(v => v.date.equals(this.datetimepicker.value.date));             if (this.tbxtva.text != "")                 queryv = queryv.where(v => v.client.numentreprise.contains(this.tbxtva.text));             if (this.checkboxvendeur.checked)             {                 employe employe = this.comboboxvendeur.selecteditem employe;                 queryv = queryv.where(v => v.employe.login.equals(employe.login));             }              this.documentbindingsource.datasource = queryv.tolist();         }         if (this.comboboxtype.text.equals("commande"))         {             iqueryable<commande> queryc = contextedao.contextedonnees.commande                .include("client")                .include("paiement")                .include("employe").orderby(c => c.commandeid);              if (this.tbxnomcli.text != "")                 queryc = queryc.where(v => v.client.nom.contains(this.tbxnomcli.text));             if (this.comboboxetat.text != "tous")                 queryc = queryc.where(v => v.etat == this.comboboxetat.text);             if (this.checkboxdate.checked)                 queryc = queryc.where(v => v.date.equals(this.datetimepicker.value.date));             if (this.tbxtva.text != "")                 queryc = queryc.where(v => v.client.numentreprise.contains(this.tbxtva.text));             if (this.checkboxvendeur.checked)             {                 employe employe = this.comboboxvendeur.selecteditem employe;                 queryc = queryc.where(v => v.employe.login.equals(employe.login));             }              this.documentbindingsource.datasource = queryc.tolist();         } 

you make generic approach:

public iqueryable<t> getdata<t>( string identifier ) {      switch( identifier )      {          case "vente":          {              return contextedao.contextedonnees.vente                                                .include("client")                                                .include("paiement")                                                .include("employe")                                                .orderby(v => v.venteid);              // more stuff               break;          }           // add more cases           default:          {              return null;          }      } } 

the call like:

iqueryable<vente> result = getdata<vente>( "vente" ); 

it solve problem won't it, because need specify type , need identifier selection perform. lead exception fast when have getdata<vente>( "otherentity" ).