Enterprise Library

怼烎@ 2021-11-02 07:36 167阅读 0赞

n Data Access Application Block

— 在项目中添加Data Access Application Block

— 1.添加引用

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— 2.编辑Web.config

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— 在代码中使用Data Access Application Block非常简单，使用DatabaseFactory可以创建一个Database对象。

Database db = DatabaseFactory.CreateDatabase("NorthwindConnection");

DbCommand cmd;

if (txtCountry.Text != string.Empty)

cmd = db.GetSqlStringCommand("select EmployeeID, FirstName, LastName, Country from Employees where Country=@Country");

db.AddInParameter(cmd, "@Country", DbType.String, txtCountry.Text);

else

cmd = db.GetSqlStringCommand("select EmployeeID, FirstName, LastName, Country from Employees");

DataSet dsEmployees = db.ExecuteDataSet(cmd);

gvEmployees.DataSource = dsEmployees.Tables\[0\];

gvEmployees.DataBind();

— 编译时若出错则将Web.config中name="dataConfiguration" 的那个section的type属性中的 PublicKeyToken去掉。

n Caching Application Block

— 在项目中添加Caching Application Block

— 1.添加引用

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— 编辑Web.config

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— 下面的代码对所有员工信息做了1分钟的缓存

Database db = DatabaseFactory.CreateDatabase("NorthwindConnection");

DbCommand cmd;

DataSet dsEmployees;

if (txtCountry.Text != string.Empty)

cmd = db.GetSqlStringCommand("select EmployeeID, FirstName, LastName, Country from Employees where Country=@Country");

db.AddInParameter(cmd, "@Country", DbType.String, txtCountry.Text);

dsEmployees = db.ExecuteDataSet(cmd);

else

cmd = db.GetSqlStringCommand("select EmployeeID, FirstName, LastName, Country from Employees");

ICacheManager cacheManager = CacheFactory.GetCacheManager("NorthwindCache");

dsEmployees = (DataSet)cacheManager\["AllEmployees"\];

if (dsEmployees == null)

dsEmployees = db.ExecuteDataSet(cmd);

AbsoluteTime expireTime = new AbsoluteTime(DateTime.Now.AddMinutes(1));

cacheManager.Add("AllEmployees", dsEmployees, CacheItemPriority.Normal,null,expireTime);

gvEmployees.DataSource = dsEmployees.Tables\[0\];

gvEmployees.DataBind();

— 前面的代码我们使用了CacheManager的Add方法，其中有个参数为params ICacheItemExpiration\[\]，我们为其传递了一个AbsoluteTime对象，事实上，所有实现ICacheItemExpiration的对象均可以放入。例如：

— AbsoluteTime 绝对时间，到指定时间点释放缓存

— SlidingTime 滑动时间，设定一个存活时间长度，时间长度逐渐变小，当为0时释放缓存，在存活期间内，若再次访问该缓存，则存活时间长度恢复初始值。

— FileDependency 当某个文件被修改时缓存过期。

n Logging Application Block

— 在项目中添加Logging Application Block

— 1.添加引用

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— 2.编辑Web.config

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— 在代码中，新建一个LogEntry，并设置相关属性后，用Logger写入日志。

cmd = db.GetSqlStringCommand("select EmployeeID,FirstName,LastName,Country from Employees");

ICacheManager cacheManager = CacheFactory.GetCacheManager("NorthwindCache");

dsEmployees = (DataSet)cacheManager\["AllEmployees"\];

if (dsEmployees == null)

dsEmployees = db.ExecuteDataSet(cmd);

AbsoluteTime expireTime = new AbsoluteTime(DateTime.Now.AddMinutes(1));

cacheManager.Add("AllEmployees", dsEmployees, CacheItemPriority.Normal, null, expireTime);

LogEntry log = new LogEntry();

log.Severity = TraceEventType.Information;

log.Categories.Add("General");

log.Message = "缓存过期，重新获取数据并写入缓存。";

log.Title = "获取数据";

Logger.Write(log);

— 使用默认的配置文件会将将日志写入Windows日志查看器，也可以在Trace Listeners中新增一个Listener，例如FlatFile TraceListener ，然后Category Source中新增一个Category，并设置新增的Listener的Reference，则在代码中属于该Category的LogEntry，均会被写到文本文件中。

n Exception Handling Application Block

— 在项目中添加

— 添加引用

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— 此处可以只选择Exception Handling Application Block ，但若要记录异常日志的话，还需要Exception Handling Logging Provider。

— 编辑Web.config

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— 添加异常策略

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— 在该策略下创建异常类型和异常的处理器

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— 在代码中捕捉到异常后，可以使用ExceptionPolicy处理异常。

try

DateTime hireDate = DateTime.Parse(txtHireDate.Text);

//...

catch (FormatException ex)

ExceptionPolicy.HandleException(ex, "Exception Policy");

转载于:https://www.cnblogs.com/adamyang/archive/2009/11/04/1595956.html

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