ConnectionStringsExpressionBuilder.EvaluateExpression(Object, BoundPropertyEntry, Object, ExpressionBuilderContext) 方法

定义

从 Web.config 文件的 <connectionStrings> 节返回一个值。Returns a value from the <connectionStrings> section of the Web.config file.

public:
 override System::Object ^ EvaluateExpression(System::Object ^ target, System::Web::UI::BoundPropertyEntry ^ entry, System::Object ^ parsedData, System::Web::Compilation::ExpressionBuilderContext ^ context);
public override object EvaluateExpression (object target, System.Web.UI.BoundPropertyEntry entry, object parsedData, System.Web.Compilation.ExpressionBuilderContext context);
override this.EvaluateExpression : obj * System.Web.UI.BoundPropertyEntry * obj * System.Web.Compilation.ExpressionBuilderContext -> obj
Public Overrides Function EvaluateExpression (target As Object, entry As BoundPropertyEntry, parsedData As Object, context As ExpressionBuilderContext) As Object

参数

target
Object

包含表达式的对象。The object that contains the expression.

entry
BoundPropertyEntry

表达式绑定到的属性。The property to which the expression is bound.

parsedData
Object

表示由 ParseExpression(String, Type, ExpressionBuilderContext) 返回的已分析数据的对象。The object that represents parsed data as returned by ParseExpression(String, Type, ExpressionBuilderContext).

context
ExpressionBuilderContext

控件或页的属性。Properties for the control or page.

返回

Object

与 Web.config 文件的 <connectionStrings> 节中某个键关联的 ObjectThe Object associated with a key in the <connectionStrings> section of the Web.config file.

例外

未能在 Web.config 文件中找到连接字符串名称。The connection string name could not be found in the Web.config file.

注解

<%$ ConnectionStrings: secureConnectionString %> 未编译的页面中遇到形式的表达式时,将调用此方法。This method is called when an expression of the form <%$ ConnectionStrings: secureConnectionString %> is encountered in a page that is not compiled. 它从 Web.config 文件的部分中检索相应的值 <connectionStrings>It retrieves the appropriate value from the <connectionStrings> section of the Web.config file. EvaluateExpression GetConnectionString 如果参数中包含连接字符串,则此方法通过调用方法来重写方法 parsedData ; GetConnectionStringProviderName 如果参数中未包含连接字符串,则通过调用方法 parsedData 来重写方法。This method overrides the EvaluateExpression method by calling the GetConnectionString method if a connection string is included in the parsedData parameter, or by calling the GetConnectionStringProviderName method if a connection string is not included in the parsedData parameter.

适用于

另请参阅