ComboBox SelectedValuePath SelectionChanged
ComboBox SelectedValuePath SelectionChanged
提问于 2016-06-06 18:29:17
我对WPF和数据库概念很陌生，我正在自学(用这个应用程序和几本书)。
我尝试过搜索，但是有很多关于如何绑定它的问题(和答案)，但不包括如何引用/使用SelectedValue和SelectedValuePath中选定的项：
概述:我在window_loaded上填充一个window_loaded，如下所示：
Private db As New Pluto_DBDataContext()
Private OrganisationTypeView As BindingListCollectionView
Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
LoadOrganisationType()
End Sub
Private Sub LoadOrganisationType()
Dim OrganisationTypeList = From EntOrgs In db.t_EntityOrgs
Join EntType In db.t_EntityTypes On EntType.ID Equals EntOrgs.FK_EntityType_ID
Order By EntOrgs.OrganisationType
Where EntOrgs.DateTime_To Is Nothing AndAlso EntType.DateTime_To Is Nothing _
AndAlso ((Not bolIndividualEntityType) And EntType.EntityType <> "Individual")
Select EntOrgs.OrganisationType, EntOrgs.ID
OrganisationType_ComboBox.DataContext = OrganisationTypeList
Me.OrganisationTypeView = CType(CollectionViewSource.GetDefaultView(OrganisationType_ComboBox.DataContext), BindingListCollectionView)
End SubXAML：
<ComboBox x:Name="OrganisationType_ComboBox" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding}" SelectedValue="{Binding OrganisationType}" SelectedValuePath="ID" DisplayMemberPath="OrganisationType"/>ComboBox_SelectionChanged:然后，我使用选定的OrganisationType来过滤客户端的ListView，如下所示(注意还有其他控件也触发了RefreshOrganisationClientList())。
这就是我的问题所在。如何获得所选值和/或该选择的ID (SelectedValuePath)。
Private Sub OrganisationType_ComboBox_SelectionChanged(sender As Object, e As SelectionChangedEventArgs) Handles OrganisationType_ComboBox.SelectionChanged
If OrganisationType_ComboBox.SelectedItem IsNot Nothing Then
RefreshOrganisationClientList()
End If
End Sub
Private Sub RefreshOrganisationClientList()
Dim sOrgType As String
Dim guOrgType_ID As Guid
Dim sOrganisationName As String
Dim sPostCode As String
Dim sOccupation As String
If OrganisationType_ComboBox.SelectedItem Is Nothing Then
sOrgType = Nothing
Else
'*****PROBLEM HERE*****
sOrgType = OrganisationType_ComboBox.SelectedItem.index(1).ToString
guOrgType_ID = OrganisationType_ComboBox.SelectedItem
'guOrgType_ID = Guid.Parse(OrganisationType_ComboBox.SelectedValuePath)
End If
MsgBox(sOrgType)
MsgBox(guOrgType_ID)
sOrganisationName = OrganisationName_TextBox.Text
sPostCode = OrgPostalCode_TextBox.Text
sOccupation = OrgOccupation_TextBox.Text
Dim FilteredClientList = From Clients In db.t_Clients
Join EntType In db.t_EntityTypes On EntType.ID Equals Clients.FK_EntityType_ID
Join EntOrgs In db.t_EntityOrgs On EntType.ID Equals EntOrgs.FK_EntityType_ID
Order By Clients.OrganisationName, Clients.Occupation, EntOrgs.OrganisationType
Where Clients.DateTime_To Is Nothing AndAlso EntType.DateTime_To Is Nothing AndAlso EntOrgs.DateTime_To Is Nothing _
AndAlso ((Not bolIndividualEntityType) And EntType.EntityType <> "Individual") _
AndAlso (If(sOrgType IsNot Nothing, EntOrgs.ID = guOrgType_ID, True)) _
AndAlso (If(sOrganisationName IsNot "", Clients.OrganisationName Like "*" & sOrganisationName & "*", True)) _
AndAlso (If(sPostCode IsNot "", Clients.Postal_Code Like "*" & sPostCode & "*", True)) _
AndAlso (If(sOccupation IsNot "", Clients.Occupation Like "*" & sOccupation & "*", True))
Select Clients.OrganisationName, EntOrgs.OrganisationType, Clients.Occupation, Clients.FormationDate, Clients.Postal_Code, Clients.ID
ExistingOrganisationClients_ListView.DataContext = FilteredClientList
Me.FilteredOrgansiationClientView = CType(CollectionViewSource.GetDefaultView(ExistingOrganisationClients_ListView.DataContext), BindingListCollectionView)
End Sub我开始认为我误解了数据绑定本身的概念，以及如何使用从数据绑定控件中选择的数据，或者我忽略了一些简单的东西。
编辑:我试着发布一个图片，但由于我是新来的，我不能这样做，所以一个描述和一个链接将不得不这样做:在下面这两个方面，“合作伙伴关系”是从ComboBox而不是“慈善”中选择的。慈善是向用户展示的清单中的第一项。
SelectedValue：SelectedValue Imgur链接含量
- OrganisationType_ComboBox.SelectedValue "Charity" Object {String}SelectedItem：SelectedItem Imgur链接含量
- OrganisationType_ComboBox.SelectedItem OrganisationType="Partnerships", ID={27775e86-0013-4b82-996f-f6c061e99b2f} Object {VB$AnonymousType_3(Of String, System.Guid)}
+ ID {27775e86-0013-4b82-996f-f6c061e99b2f} System.Guid
- OrganisationType "Partnerships" String编辑:对于以后偶然发现这个问题的人，下面是更新以解决上述问题的方法。再次感谢！：
XAML：
<ComboBox x:Name="OrganisationType_ComboBox" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding}" SelectedValuePath="ID" DisplayMemberPath="OrganisationType"/>ComboBox_SelectionChanged：
Private Sub RefreshOrganisationClientList()
Dim sOrgType As String
Dim guOrgType_ID As Guid
Dim sOrganisationName As String
Dim sPostCode As String
Dim sOccupation As String
If OrganisationType_ComboBox.SelectedItem Is Nothing Then
guOrgType_ID = Nothing
Else
guOrgType_ID = OrganisationType_ComboBox.SelectedValue
End If
sOrganisationName = OrganisationName_TextBox.Text
sPostCode = OrgPostalCode_TextBox.Text
sOccupation = OrgOccupation_TextBox.Text
Dim FilteredClientList = From Clients In db.t_Clients
Join EntType In db.t_EntityTypes On EntType.ID Equals Clients.FK_EntityType_ID
Join EntOrgs In db.t_EntityOrgs On EntType.ID Equals EntOrgs.FK_EntityType_ID
Order By Clients.OrganisationName, Clients.Occupation, EntOrgs.OrganisationType
Where Clients.DateTime_To Is Nothing AndAlso EntType.DateTime_To Is Nothing AndAlso EntOrgs.DateTime_To Is Nothing _
AndAlso ((Not bolIndividualEntityType) And EntType.EntityType <> "Individual") _
AndAlso (If(guOrgType_ID <> Guid.Empty, EntOrgs.ID = guOrgType_ID, True)) _
AndAlso (If(sOrganisationName IsNot "", Clients.OrganisationName Like "*" & sOrganisationName & "*", True)) _
AndAlso (If(sPostCode IsNot "", Clients.Postal_Code Like "*" & sPostCode & "*", True)) _
AndAlso (If(sOccupation IsNot "", Clients.Occupation Like "*" & sOccupation & "*", True))
Select Clients.OrganisationName, EntOrgs.OrganisationType, Clients.Occupation, Clients.FormationDate, Clients.Postal_Code, Clients.ID
ExistingOrganisationClients_ListView.DataContext = FilteredClientList
Me.FilteredOrgansiationClientView = CType(CollectionViewSource.GetDefaultView(ExistingOrganisationClients_ListView.DataContext), BindingListCollectionView)
End Sub回答 1
Stack Overflow用户
回答已采纳
发布于 2016-06-06 18:40:26
在这里，您可以使用匿名类型的实例填充组合框。
Dim OrganisationTypeList = From EntOrgs In db.t_EntityOrgs
Join EntType In db.t_EntityTypes On EntType.ID Equals EntOrgs.FK_EntityType_ID
Order By EntOrgs.OrganisationType
Where EntOrgs.DateTime_To Is Nothing AndAlso EntType.DateTime_To Is Nothing _
AndAlso ((Not bolIndividualEntityType) And EntType.EntityType <> "Individual")
Select EntOrgs.OrganisationType, EntOrgs.ID
OrganisationType_ComboBox.DataContext = OrganisationTypeList当用户选择某项内容时，ComboBox.SelectedItem将是该匿名类型的实例。您需要几行反射代码才能从中获取任何属性值，因为您不能将其转换为任何东西。
幸运的是，您能够很好地将SelectedValuePath="ID"设置在组合框上。如果SelectedValuePath指定了实际存在于所选项上的属性，则ComboBox将为您完成所有反射工作，从所选项中获取该命名属性的值，并将其填充到SelectedValue属性中。在这种情况下，应该是SelectedItem.ID。
Guid selectedID = (Guid)OrganisationType_ComboBox.SelectedValue;我猜EntOrgs.ID是Guid型的。如果不是的话，不管它是什么类型，都用它代替。
int selectedID = (int)OrganisationType_ComboBox.SelectedValue;或者别的什么。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/37664445
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