ConnectionStringsExpressionBuilder Class
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Retrieves, or generates code to retrieve, values from the <connectionStrings
> section of the Web.config file.
public ref class ConnectionStringsExpressionBuilder : System::Web::Compilation::ExpressionBuilder
public class ConnectionStringsExpressionBuilder : System.Web.Compilation.ExpressionBuilder
type ConnectionStringsExpressionBuilder = class
inherit ExpressionBuilder
Public Class ConnectionStringsExpressionBuilder
Inherits ExpressionBuilder
- Inheritance
The following code example demonstrates how to declaratively use a SqlDataSource control to retrieve data from a computer running Microsoft SQL Server and display it in a GridView control.
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
DataSourceMode="DataReader"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommand="SELECT FirstName, LastName, Title FROM Employees">
</asp:SqlDataSource>
<asp:GridView
id="GridView1"
runat="server"
DataSourceID="SqlDataSource1">
</asp:GridView>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
DataSourceMode="DataReader"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommand="SELECT FirstName, LastName, Title FROM Employees">
</asp:SqlDataSource>
<asp:GridView
id="GridView1"
runat="server"
DataSourceID="SqlDataSource1">
</asp:GridView>
</form>
</body>
</html>
The code retrieves the following connection string from the Web.config file.
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
<connectionStrings>
<add name="MyNorthwind" connectionString="Data
Source=localhost;Integrated Security=SSPI;Initial
Catalog=Northwind;" providerName="System.Data.SqlClient" />
</connectionStrings>
</configuration>
The ConnectionStringsExpressionBuilder class provides access to values in the <connectionStrings>
section of the Web.config file. The <connectionStrings>
section of the Web.config file contains connection string values in name/value pairs.
A connection string value is retrieved by assigning an expression of the form
<%$ ConnectionStrings: secureConnectionString %>
to a control property. The part of the expression before the colon (:) designates the type of expression to be retrieved, and the part after the colon signifies the name of the connection string. The preceding expression would retrieve the following value from the Web.config file.
<connectionStrings>
<add name="secureConnectionString" connectionString="Data
Source=localhost;Integrated Security=SSPI;Initial
Catalog=Northwind;" providerName="System.Data.SqlClient" />
</connectionStrings>
When the page parser encounters an expression with the prefix ConnectionStrings
, it creates an instance of the ConnectionStringsExpressionBuilder class to handle the expression.
If the expression is encountered in a page that will be compiled, the ConnectionStringsExpressionBuilder object generates code that retrieves the specified connection string from the Web.config file. If the expression is encountered in a page that will not be compiled, the ConnectionStringsExpressionBuilder object returns the value from the Web.config file when the page is parsed.
Connection |
Initializes a new instance of the ConnectionStringsExpressionBuilder class. |
Supports |
Returns a value indicating whether an expression can be evaluated in a page that is not compiled. |
Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
Evaluate |
Returns a value from the < |
Get |
Returns a code expression to evaluate during page parsing. |
Get |
Returns a connection string from the < |
Get |
Returns the connection string provider from the < |
Get |
Serves as the default hash function. (Inherited from Object) |
Get |
Gets the Type of the current instance. (Inherited from Object) |
Memberwise |
Creates a shallow copy of the current Object. (Inherited from Object) |
Parse |
Returns an object that represents the parsed expression. |
To |
Returns a string that represents the current object. (Inherited from Object) |
Produkt | Versjoner |
---|---|
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
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