ASP.Net/Language Basics/Variable Scope — различия между версиями

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Версия 18:30, 26 мая 2010

block-level variables (C#)

   <source lang="csharp">

<%@ Page Language="c#" %> <script runat="server"> void Page_Load() { 

 if(1==1)
 {
     string strBlockLevelVariable;
     strBlockLevelVariable = "Very Short Lived!";
 
     lblMessage.Text = strBlockLevelVariable;
 }

} </script> <html> <head> <title>Creating Variables Example</title> </head> <body> 

   <asp:Label runat="server" ID="lblMessage"/>

</body> </html> 

      </source>


Define page level variables (VB.net)

   <source lang="csharp">

<%@ Page Language="VB" %> <script runat="server"> 

   Dim myFirstNumber, mySecondNumber As Integer
   
   Sub SetVarsToInitialValues()
     myFirstNumber = 7
     mySecondNumber = 8
   
     Label1.Text = myFirstNumber
     Label2.Text = mySecondNumber
   End Sub
   
   Sub Button1_Click(sender As Object, e As EventArgs)
     SetVarsToInitialValues()
     Label3.Text = myFirstNumber + mySecondNumber
   End Sub
   
   Sub Button2_Click(sender As Object, e As EventArgs)
     SetVarsToInitialValues()
     Label3.Text = myFirstNumber - mySecondNumber
   End Sub

</script> <html> <head> </head> <body> 

   <form runat="server">

<asp:Label id="Label1" runat="server">Label</asp:Label>  + <asp:Label id="Label2" runat="server">Label</asp:Label>  = <asp:Label id="Label3" runat="server">Label</asp:Label>

<asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Add"></asp:Button> <asp:Button id="Button2" onclick="Button2_Click" runat="server" Text="Subtract"></asp:Button> 

   </form>

</body> </html> 

      </source>


Function Level variables (C#)

   <source lang="csharp">

<%@ Page Language="C#" Debug="true" %> <script runat="server"> 

   void Page_Load()
   {
     string strMyFuncVariable = "Function-Level Variable";
     if(Page.IsPostBack)
     {
         string strMyBlockVariableUsedInside = "Block Variable Used In Block";
         lblMessageBlockInBlock.Text = strMyBlockVariableUsedInside;
         lblMessageFunction.Text = strMyFuncVariable;
     }
   
   }

</script> <html> <head> 

   <title>Variable Scope</title>

</head> <body> 

   <form runat="server">
       <asp:Label id="lblMessageBlockInBlock" runat="server" text="DEFAULT - BlockInBlock"></asp:Label>
       

       <asp:Label id="lblMessageFunction" runat="server" text="DEFAULT - Function"></asp:Label>
       

       <asp:Button id="Button1" runat="server" Text="Submit"></asp:Button>
   </form>

</body> </html> 

      </source>


Local variable inside a function (VB.net)

   <source lang="csharp">

<script language="vb" runat="server"> Sub Page_Load() 

   Response.Write ("
Calling Subroutine 1...")
   Call Subroutine_1()
   Response.Write ("
Calling Subroutine 2...")
   Call Subroutine_2()
   Response.Write ("
Calling Subroutine 1...")
   Call Subroutine_1()

End Sub 

 Sub Subroutine_1()
   Dim Different As String
   Different = "Hello I"m the variable Different in Subroutine 1"
   Response.Write (Different)
 End Sub
 Sub Subroutine_2()
   Dim Different As String
   Different = "Hello I"m the variable Different in Subroutine 2"
   Response.Write (Different)
 End Sub

</script> <html> <head> <title>Scope</title> </head> <body> </body> </html> 

      </source>


Page level variable and function level variable (VB.net)

   <source lang="csharp">

<script language="vb" runat="server"> 

   Dim Global As String ="
Hello I"m a persistent global variable"

Sub Page_Load() 

   Response.Write (Global)     
   Response.Write ("
Calling Subroutine 1...")
   Call Subroutine_1()
   Response.Write ("
Calling Subroutine 2...")
   Call Subroutine_2()
   Response.Write ("
Calling Subroutine 1...")
   Call Subroutine_1()

End Sub 

 Sub Subroutine_1()
   Dim Different As String
   Different = "Hello I"m the variable Different in Subroutine 1"
   Response.Write (Different)
   Response.Write (Global)
 End Sub
 Sub Subroutine_2()
   Dim Different As String
   Different = "Hello I"m the variable Different in Subroutine 2"
   Response.Write (Different)
   Response.Write (Global)
 End Sub

</script> <html> <head> <title>Scope</title> </head> <body> </body> </html> 

      </source>


Page Level Variable (C#)

   <source lang="csharp">

<%@ Page Language="C#" Debug="true" %> <script runat="server"> 

        string strVariableGlobal = "Variable Global: Use me anyplace on the page";
   
        void Page_Load()
        {
           string strMyVariable1 = "Block Variable Used In Block";
   
           if (1==1)
           {
             string strMyVariable2 = "Block Variable Used In Block";
             string strMyVariable3 = "Block Variable Used After Block";
             lblMessageBlockInBlock.Text = strVariableGlobal;
   
           }
   
           lblMessageProcedure.Text = strVariableGlobal;
           SubProcedure2();
        }  
   
       void SubProcedure2()
       {
           lblMessageBlockOutBlock.Text = strVariableGlobal;
       }

</script> <html> <head> 

   <title>Variable Scope</title>

</head> <body> 

   <form runat="server">
       <asp:Label id="lblMessageBlockInBlock" runat="server" text="DEFAULT - BlockInBlock"/>
       

       <asp:Label id="lblMessageBlockOutBlock" runat="server" text="DEFAULT - BlockOutBlock"></asp:Label>
       

       <asp:Label id="lblMessageProcedure" runat="server" text="DEFAULT - Procedure"></asp:Label>
       

   </form>

</body> </html> 

      </source>
Источник — «http://nfex.ru/index.php?title=ASP.Net/Language_Basics/Variable_Scope&oldid=2197»