這個(gè)組件的主要作用是將設(shè)置(Setttings)的內(nèi)容谓媒，根據(jù)鍵值關(guān)系填充到已經(jīng)存在的實(shí)體或靜態(tài)類中
先來一個(gè)最簡單的例子
有一個(gè)叫tests的項(xiàng)目，app.config的配置文件內(nèi)容如下：
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="tests.datetime" value="2017-1-1 0:0:0"/>
<add key="tests.url" value="http://baidu.com"/>
<add key="tests.maxlength" value="9999.99"/>
<add key="tests.minlength" value="0.01"/>
<add key="tests.delay" value="1000"/>
<add key="tests.enable" value="true"/>
</appSettings>
</configuration>
* 在使用中我比較喜歡在設(shè)置前加上項(xiàng)目的前綴或命名空間, 以便區(qū)分不同項(xiàng)目間的同名設(shè)置項(xiàng)
過去在項(xiàng)目中使用配置文件一般是
static void Main(string[] args)
{
var timeValue = System.Configuration.ConfigurationManager.AppSettings["tests.datetime"];
if(!DateTime.TryParse(timeValue, out var time))
{
time = new DateTime(1970, 1, 1);
}
Console.WriteLine(time);
}
不僅臃腫，而且不易閱讀和維護(hù)
好一點(diǎn)的做法是
static class Settings
{
static Settings()
{
var settings = System.Configuration.ConfigurationManager.AppSettings;
if (DateTime.TryParse(settings["tests.datetime"], out var time))
{
DateTime = new DateTime(1970, 1, 1);
}
if (Uri.TryCreate(settings["tests.url"],UriKind.RelativeOrAbsolute,out var url))
{
Url = url;
}
if (float.TryParse(settings["tests.maxlength"], out var maxlength))
{
MaxLength = maxlength;
}
if (float.TryParse(settings["tests.minlength"], out var minlength))
{
MinLength = minlength;
}
if (int.TryParse(settings["tests.delay"], out var delay))
{
Delay = delay;
}
if (bool.TryParse(settings["tests.enable"], out var enable))
{
Enable = enable;
}
}
public static DateTime DateTime { get; private set; } = new DateTime(1970, 1, 1);
public static Uri Url { get; private set; }
public static float MaxLength { get; private set; }
public static float MinLength { get; private set; }
public static int Delay { get; private set; }
public static bool Enable { get; private set; }
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine(Settings.DateTime);
Console.WriteLine(Settings.Url);
Console.WriteLine(Settings.MaxLength);
Console.WriteLine(Settings.MinLength);
Console.WriteLine(Settings.Delay);
Console.WriteLine(Settings.Enable);
}
}
這例子中是6個(gè)設(shè)置缺脉，而實(shí)際如果有10個(gè)甚至20個(gè)設(shè)置上真，那將變得非常枯燥
所以有了 SettingsFetcher
[SettingsGroupName("tests")]
static class Settings
{
static Settings() => SettingsFetcher.Fill(typeof(Settings), false);
public static DateTime DateTime { get; private set; } = new DateTime(1970, 1, 1);
public static Uri Url { get; private set; }
public static float MaxLength { get; private set; }
public static float MinLength { get; private set; }
public static int Delay { get; private set; }
public static bool Enable { get; private set; }
}
使用 [SettingsGroupName("tests")] 這個(gè)特性來設(shè)置前綴绢馍，名稱直接根據(jù)屬性名稱匹配
更多的用法可以參考
