兩隻小虎,一隻豬

開發Net. 程式開發時會將程式的參數檔案寫到app.config中

大部分使用者自訂的參數會寫在applicationSettings中
不過這樣的寫法沒有模組化
原始的applicationSettings

<applicationSettings>
   <My.MySettings>
      <setting name="HRDBSchema" serializeAs="String">
      <value>HR</value>
      <setting name="RDDBSchema" serializeAs="String">
      <value>RD</value> 
      </setting>
   </My.MySettings>
</applicationSettings>

config 改成下面寫法,把相關的參數寫在同一個tag 中,類似connectionStrings tag的寫法

<DBSetting>
   <Group DBNAME="HRDB" SCHEMA="HR">
   <Group DBNAME="RDDB" SCHEMA="RD">
</DBSetting>

1. 加入System.Configuration參考

2. 在configSections中新增一個section tag

<configuration>
  <configSections>
    <section name="DBSetting" type="WindowsApplication1.MyConfigHandler, WindowsApplication1" />      
  </configSections>
  <DBSetting>
    <Group DBNAME="HRDB" SCHEMA="HR">
    <Group DBNAME="RDDB" SCHEMA="RD">
  </DBSetting>
<configuration>

3. 新增DBSetting類別

Public Class DBSetting
    Public DBNAME As String
    Public SCHEMA As String
End Class

4. 新增MyConfigHandler類別

Imports System
Imports System.Configuration
Imports System.Xml

Public Class MyConfigHandler : Implements IConfigurationSectionHandler

  Public Function Create(ByVal parent As Object, ByVal configContext As Object, ByVal section As System.Xml.XmlNode) As Object Implements System.Configuration.IConfigurationSectionHandler.Create
    Dim olist As New List(Of DBSetting)
    Dim oSchSetting As DBSetting
    For Each JobNode As XmlNode In section.ChildNodes
      oSchSetting = New DBSetting()
      With oSchSetting
        .DBNAME = JobNode.Attributes("DBNAME").InnerText
        .SCHEMA = JobNode.Attributes("SCHEMA").InnerText
      End With 
      olist.Add(oSchSetting)
    Next
    Return olist
  End Function
End Class

5. 在程式中引用

Imports System.Configuration
Public Class Form1
    Public Sub New()
    ' 此為 Windows Form 設計工具所需的呼叫。
    InitializeComponent()
    ' 在 InitializeComponent() 呼叫之後加入任何初始設定。
        
    Dim DBList As New Generic.List(Of DBSetting)
    Dim DBSchemaList As New Generic.LinkedList(Of String)
    Dim DBSchemaDic As New Generic.Dictionary(Of String, String)

    ' Get Schedule Run and ETL setting from app.config
    DBList = CType(ConfigurationManager.GetSection("DBSetting"), Generic.List(Of DBSetting))
    For Each db As DBSetting In DBList
      DBSchemaDic.Add(db.DBNAME, db.SCHEMA)
    Next
  End Sub
End Class