{"id":242,"date":"2009-09-05T17:52:00","date_gmt":"1970-01-01T00:00:00","guid":{"rendered":"http:\/\/www.yazilimmutfagi.com\/?p=242"},"modified":"2009-09-05T17:52:00","modified_gmt":"1970-01-01T00:00:00","slug":"visual-basic-net-select-case-kullanimi","status":"publish","type":"post","link":"https:\/\/www.yazilimmutfagi.com\/index.php\/2009\/09\/05\/visual-basic-net-select-case-kullanimi\/","title":{"rendered":"Visual Basic.NET Select Case kullanimi"},"content":{"rendered":"

\n<\/p>\n

Select<\/span><\/b> döngüsü karmasik ve uzun if-Else<\/b> döngülerini daha anlasilir, kolay ve zevkli hâle getiren bir alternatiftir. Programlarimizi yalnizca If-Else<\/b> döngüleri kullanarak da yazabilirdik, fakat Select<\/b> bazi durumlarda çok daha faydali ve akillica olabilir. Diyelim ki haftanin günlerini gösteren bir kod parçasi yazacagiz.<\/o:p><\/span><\/p>\n

Öncelikle iki tane degisken tanimlariz: gunAdi (string<\/b>), gunSirasi (integer<\/b>). <\/o:p><\/span><\/p>\n

Bu programi önce If-Else<\/b> ile yazalim;<\/span><\/p>\n

.<\/a>
\n<\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n\n \n \n
\n

Dim<\/span> gunSirasi As<\/span> Integer<\/span><\/span><\/o:p><\/span><\/p>\n

Dim<\/span> gunAdi As<\/span> String<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n

If<\/span> gunSirasi = 1 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "pazartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 2 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "sali"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 3 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   <\/span>gunAdi = "çarsamba"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 4 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "persembe"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 5 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "cuma"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 6 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "cumartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

ElseIf<\/span> gunSirasi = 7 Then<\/span><\/span><\/o:p><\/span><\/p>\n

   gunAdi = "pazar"<\/span><\/span><\/o:p><\/span><\/p>\n

End<\/span> If<\/span><\/span><\/o:p><\/span><\/p>\n <\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n

 <\/o:p><\/span> <\/span>Simdi de ayni isi görecek olan kodlarimizi Select döngüsü ile yazalim:<\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n\n \n \n
\n

Select<\/span> Case<\/span> gunSirasi<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 1<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "pazartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 2<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "sali"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 3<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "çarsamba"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 4<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "persembe"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 5<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "cuma"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 6<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "cumartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 7<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "pazar"<\/span><\/span><\/o:p><\/span><\/p>\n

End<\/span> Select<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n <\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n

       <\/span>.<\/a><\/span><\/o:p><\/span><\/p>\n

Select döngüsünün içine baska neler yerlestirebilirdik bir bakalim.<\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n\n \n \n
\n

        Select<\/span> Case<\/span> gunSirasi<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 1<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "pazartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 2<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "sali"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 3<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "çarsamba"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 4<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "persembe"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 5<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "cuma"<\/span><\/span><\/o:p><\/span><\/p>\n

                MessageBox.Show("mubarek gün"<\/span>)<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 6<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "cumartesi"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 7<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "pazar"<\/span><\/span><\/o:p><\/span><\/p>\n

        End<\/span> Select<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n <\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n

 <\/o:p><\/span>Veya;<\/o:p><\/span> <\/o:p><\/span><\/p>\n\n \n \n
\n

Select<\/span> Case<\/span> gunSirasi<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 1, 2, 3, 4, 5<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "hafta içi"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 6, 7<\/span><\/o:p><\/span><\/p>\n

                gunAdi = "hafta sonu"<\/span><\/span><\/o:p><\/span><\/p>\n

            Case<\/span> Else<\/span><\/span><\/o:p><\/span><\/p>\n

                gunAdi = "bilinmeyen gün"<\/span><\/span><\/o:p><\/span><\/p>\n

        End<\/span> Select<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n <\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n


\n<\/o:p><\/span><\/p>\n

‘Case Else’ <\/span><\/b>ibaresine dikkat etmissinizdir! Eger bizim planladigimizdan farkli bir gunSirasi girilirse, örnegin 8, o zaman Case Else <\/b>blogu devreye giriyor ve bu blokta verilen emirleri yerine getiriyor. Ihtiyaç olmadigi müddetçe kullanilmasi zorunlu degildir.<\/o:p><\/span> <\/o:p><\/span><\/p>\n

Select<\/span><\/b> komutu görüldügü gibi çok kullanislidir. Fakat programimizda koyacagimiz sartlari iyi formüle etmek gerekir.<\/o:p><\/span><\/p>\n

Misal olarak söyle bir program daha yazalim; iki tane sayi verilsin ve ekrana bu sayilardan hangisinin büyük hangisinin küçük oldugunu yazdiralim:<\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n\n \n \n
\n

        Dim<\/span> a, b As<\/span> Integer<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n

        Select<\/span> Case<\/span> a – b<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> Is<\/span> > 0<\/span><\/o:p><\/span><\/p>\n

                MessageBox.Show(CStr<\/span>(a) & ">"<\/span> & CStr<\/span>(b))<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> Is<\/span> < 0<\/span><\/o:p><\/span><\/p>\n

                MessageBox.Show(CStr<\/span>(a) & "<"<\/span> & CStr<\/span>(b))<\/span><\/o:p><\/span><\/p>\n

            Case<\/span> 0<\/span><\/o:p><\/span><\/p>\n

                MessageBox.Show(CStr<\/span>(a) & "="<\/span> & CStr<\/span>(b))<\/span><\/o:p><\/span><\/p>\n

        End<\/span> Select<\/span><\/span><\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n <\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n

 <\/o:p><\/span>a – b isleminin sonucuna göre bir islem yapiyor.<\/o:p><\/span><\/p>\n

 <\/span>Not:<\/span><\/b> CStr<\/span>(a) komutu Integer <\/span>olan ‘a’ degiskenini String<\/span>‘e çevirir. Bu program için sart degildi fakat bazen gereklidir.<\/span> <\/o:p><\/span><\/p>\n

 <\/o:p><\/span><\/p>\n

 <\/o:p><\/p>","protected":false},"excerpt":{"rendered":"

Visual Basic.Net ile select case komutunu kullanimi ve basit örnekler.<\/p>\n","protected":false},"author":519,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[418],"tags":[5576,4945,4571,4209,5308,5825],"_links":{"self":[{"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/posts\/242"}],"collection":[{"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/users\/519"}],"replies":[{"embeddable":true,"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/comments?post=242"}],"version-history":[{"count":0,"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/posts\/242\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/media?parent=242"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/categories?post=242"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.yazilimmutfagi.com\/index.php\/wp-json\/wp\/v2\/tags?post=242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}