確定資料夾層級查詢支援自定義項目屬性
此範例示範如何確保當您將自定義屬性新增至項目類型時，也會將 屬性新增至資料夾，以便在資料夾層級查詢該自定義屬性。
範例
此程式代碼範例示範如何使用 UserDefinedProperties 物件和 UserDefinedProperty 物件，以確保當您將自定義屬性新增至專案類型時，也會將屬性新增至資料夾，以便在資料夾層級查詢該自定義屬性。
當您在 UserProperties 集合上使用 Add 方法將自訂屬性新增至專案時，可以將 AddToFolderFields 參數指定為 true，將屬性新增至資料夾。 不過，自定義屬性可能不會因為開發人員錯誤或用戶動作而新增至所需的資料夾，例如透過 Outlook 字段選擇器移除自定義屬性，或將專案移至另一個資料夾。 因此，使用該自定義屬性之 Items 物件的 Find 方法和 Restrict 方法將會失敗。 藉由使用 UserDefinedProperties 物件，您可以測試您的自訂屬性是否存在於資料夾中，並在自定義屬性不存在或是否已移除時新增自定義屬性。
若要將 UserDefinedProperty 物件所代表的自訂屬性保存在資料夾中，您必須在專案中儲存具有相同名稱的自定義屬性。 將值儲存在資料夾的 UserDefinedProperty 對象中沒有任何作用。 您必須設定專案的 UserProperties 集合，才能存取您要設定的 UserProperty 物件，然後在 UserProperty 對象上設定值。 請務必在專案上呼叫 Save 方法，以保存您的變更。
If you use Visual Studio to test this code example, you must first add a reference to the Microsoft Outlook 15.0 Object Library component and specify the Outlook variable when you import the Microsoft.Office.Interop.Outlook namespace. The Imports or using statement must not occur directly before the functions in the code example but must be added before the public Class declaration. The following lines of code show how to do the import and assignment in Visual Basic and C#.
Imports Outlook = Microsoft.Office.Interop.Outlook
using Outlook = Microsoft.Office.Interop.Outlook;
Private Sub DemoUserDefinedProperty()
Dim folder As Outlook.Folder = _
CType(Application.ActiveExplorer().CurrentFolder(), _
Outlook.Folder)
Dim post As Outlook.PostItem = CType( _
folder.Items.Add("IPM.Post"), Outlook.PostItem)
' Add UserProperty to PostItem
post.UserProperties.Add("ColorID", _
Outlook.OlUserPropertyType.olText, False)
post.UserProperties("ColorID").Value = "Green"
post.Subject = "UserProperty Example"
post.Save()
Dim findPost As Outlook.PostItem
Try
' Items.Find will fail unless custom property
' is defined in the folder
findPost = _
CType(folder.Items.Find("[ColorID] = 'Green'"), _
Outlook.PostItem)
Catch ex As Exception
Debug.WriteLine(ex.Message)
End Try
' Add ColorID field to the folder
folder.UserDefinedProperties.Add("ColorID", _
Outlook.OlUserPropertyType.olText)
' Now the find works ok
Dim findPostOK As Outlook.PostItem
Try
findPostOK = _
CType(folder.Items.Find("[ColorID] = 'Green'"), _
Outlook.PostItem)
If Not (findPostOK Is Nothing) Then
Debug.WriteLine("Found PostItem")
End If
' Cleanup by deleting PostItem and ColorID
findPostOK.Delete()
Dim userProperty As Outlook.UserDefinedProperty = _
folder.UserDefinedProperties("ColorID")
userProperty.Delete()
Catch ex As Exception
Debug.WriteLine(ex.Message)
End Try
End Sub
private void DemoUserDefinedProperty()
{
Outlook.Folder folder =
Application.ActiveExplorer().CurrentFolder
as Outlook.Folder;
Outlook.PostItem post = folder.Items.Add("IPM.Post")
as Outlook.PostItem;
// Add UserProperty to PostItem
post.UserProperties.Add("ColorID",
Outlook.OlUserPropertyType.olText,
false, Type.Missing);
post.UserProperties["ColorID"].Value = "Green";
post.Subject = "UserProperty Example";
post.Save();
Outlook.PostItem findPost;
try
{
// Items.Find will fail unless custom property
// is defined in the folder
findPost =
folder.Items.Find("[ColorID] = 'Green'")
as Outlook.PostItem;
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
// Add ColorID field to the folder
folder.UserDefinedProperties.Add("ColorID",
Outlook.OlUserPropertyType.olText,
Type.Missing, Type.Missing);
// Now the find works ok
Outlook.PostItem findPostOK;
try
{
findPostOK =
folder.Items.Find("[ColorID] = 'Green'")
as Outlook.PostItem;
if (findPostOK != null)
{
Debug.WriteLine("Found PostItem");
}
// Cleanup by deleting PostItem and ColorID
findPostOK.Delete();
Outlook.UserDefinedProperty userProperty =
folder.UserDefinedProperties["ColorID"];
userProperty.Delete();
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
}