保存自訂物件
只要您建立的自訂物件其屬性只有使用簡單的資料類型，例如 integer 與 string，就不需要為這些自訂物件實作自訂持續性。 預設的持續性實作可以儲存物件的中繼資料，及其所有屬性值。
不過，如果您的物件具有使用複雜資料類型的屬性，或是如果您想要在載入和儲存屬性值時，在它們上面執行自訂處理，可以實作 IDTSComponentPersist 介面及其 LoadFromXML 與 SaveToXML 方法。 在這些方法中，您從封裝的 XML 定義載入 XML 片段 (或是將它儲存到封裝的 XML 定義)，而 XML 片段包含物件的屬性以及其目前的值。 並未定義這個 XML 片段的格式，它必須只能是格式正確的 XML。
.gif "重要事項") 重要事項 |
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當您實作自訂持續性時，必須保存物件的所有屬性，包括繼承的屬性和您加入的自訂屬性。 |
範例
雖然 SQL Server 自訂連接管理員範例並不需要 string 類型之三個屬性的自訂持續性，不過下列程式碼所顯示的自訂程式碼範例，將需要保存連接管理員及其屬性。 包含此程式碼的類別必須實作 IDTSComponentPersist 介面。
Private Const PERSIST_ELEMENT As String = "SqlConnectionManager"
Private Const PERSIST_SERVER As String = "Server"
Private Const PERSIST_DATABASE As String = "Database"
Private Const PERSIST_CONNECTIONSTRING As String = "ConnectionString"
Public Sub LoadFromXML(ByVal node As System.Xml.XmlElement, _
ByVal infoEvents As Microsoft.SqlServer.Dts.Runtime.IDTSInfoEvents) _
Implements Microsoft.SqlServer.Dts.Runtime.IDTSComponentPersist.LoadFromXML
Dim propertyNode As XmlNode
' Make sure that the correct node is being loaded.
If node.Name <> PERSIST_ELEMENT Then
Throw New Exception("Persisted element is not of type " & PERSIST_ELEMENT)
End If
' Load the three properties of the object from XML into variables.
For Each propertyNode In node.ChildNodes
Select Case propertyNode.Name
Case PERSIST_SERVER
_serverName = propertyNode.InnerText
Case PERSIST_DATABASE
_databaseName = propertyNode.InnerText
Case PERSIST_CONNECTIONSTRING
_connectionString = propertyNode.InnerText
End Select
Next
End Sub
Public Sub SaveToXML(ByVal doc As System.Xml.XmlDocument, _
ByVal infoEvents As Microsoft.SqlServer.Dts.Runtime.IDTSInfoEvents) _
Implements Microsoft.SqlServer.Dts.Runtime.IDTSComponentPersist.SaveToXML
Dim elementRoot As XmlElement
Dim propertyNode As XmlNode
' Create a new node to persist the object and its properties.
elementRoot = doc.CreateElement(String.Empty, PERSIST_ELEMENT, String.Empty)
' Save the three properties of the object from variables into XML.
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_SERVER, String.Empty)
propertyNode.InnerText = _serverName
elementRoot.AppendChild(propertyNode)
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_DATABASE, String.Empty)
propertyNode.InnerText = _databaseName
elementRoot.AppendChild(propertyNode)
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_CONNECTIONSTRING, String.Empty)
propertyNode.InnerText = _connectionString
elementRoot.AppendChild(propertyNode)
doc.AppendChild(elementRoot)
End Sub
private const string PERSIST_ELEMENT = "SqlConnectionManager";
private const string PERSIST_SERVER = "Server";
private const string PERSIST_DATABASE = "Database";
private const string PERSIST_CONNECTIONSTRING = "ConnectionString";
public void LoadFromXML(System.Xml.XmlElement node,
Microsoft.SqlServer.Dts.Runtime.IDTSInfoEvents infoEvents)
{
// Make sure that the correct node is being loaded.
if (node.Name != PERSIST_ELEMENT)
{
throw new Exception("Persisted element is not of type " + PERSIST_ELEMENT);
}
// Save the three properties of the object from variables into XML.
foreach (XmlNode propertyNode in node.ChildNodes)
{
switch (propertyNode.Name)
{
case PERSIST_SERVER:
_serverName = propertyNode.InnerText;
break;
case PERSIST_DATABASE:
_databaseName = propertyNode.InnerText;
break;
case PERSIST_CONNECTIONSTRING:
_connectionString = propertyNode.InnerText;
break;
}
}
}
public void SaveToXML(System.Xml.XmlDocument doc,
Microsoft.SqlServer.Dts.Runtime.IDTSInfoEvents infoEvents)
{
XmlElement elementRoot;
XmlNode propertyNode;
// Create a new node to persist the object and its properties.
elementRoot = doc.CreateElement(String.Empty, PERSIST_ELEMENT, String.Empty);
// Save the three properties of the object from variables into XML.
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_SERVER, String.Empty);
propertyNode.InnerText = _serverName;
elementRoot.AppendChild(propertyNode);
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_DATABASE, String.Empty);
propertyNode.InnerText = _databaseName;
elementRoot.AppendChild(propertyNode);
propertyNode = doc.CreateNode(XmlNodeType.Element, PERSIST_CONNECTIONSTRING, String.Empty);
propertyNode.InnerText = _connectionString;
elementRoot.AppendChild(propertyNode);
doc.AppendChild(elementRoot);
}
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