我有一個wpf頁面託管在一個窗口中。但是當我嘗試使用這個時,我得到了Null異常。 它的作品,然後我在另一種方法,但不是在alla方法中使用此代碼爲什麼是這樣? 請指教。c#WPF不能獲得父窗口
NewPage page = new NewPage();
Window w = Window.GetWindow(this.Parent);
w.Content = page;
編輯:
繼承人的完整代碼:
public HandOverListPage() {
InitializeComponent();
_settings = new Settings();
}
public void ShowCurrentInUseAssignment() {
_currentDoc = (App.Current as App).SelectedHandOverDoc;
var r = from item in (App.Current as App).SelectedHandOverDoc.Items
where item.Status != 20
select item;
if(r.Count() == 0) {
//Report assignment to QP with status finished
ReportAssignment();
HandOverPage page = new HandOverPage();
Window w = Window.GetWindow(this.Parent);
w.Content = page;
return;
} else {
ICollectionView view = CollectionViewSource.GetDefaultView((App.Current as App).SelectedHandOverDoc.Items);
view.SortDescriptions.Add(new SortDescription("Status", ListSortDirection.Ascending));
ListBoxAssignmentItems.ItemsSource = view;
}
TxtBlockCounter.Text = r.Count().ToString();
}
錯誤:
{ 「值不能爲空\ r \ n參數名:DependencyObject的」}
使用立即窗口時我得到這個
?this.GetType()
{Name = "HandOverListPage" FullName = "QP_Truck.Pages.HandOverListPage"}
[System.RuntimeType]: {Name = "HandOverListPage" FullName = "QP_Truck.Pages.HandOverListPage"}
base {System.Reflection.MemberInfo}: {Name = "HandOverListPage" FullName = "QP_Truck.Pages.HandOverListPage"}
Assembly: {QP Truck, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null}
AssemblyQualifiedName: "QP_Truck.Pages.HandOverListPage, QP Truck, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
Attributes: Public | BeforeFieldInit
BaseType: {Name = "Page" FullName = "System.Windows.Controls.Page"}
ContainsGenericParameters: false
DeclaringMethod: 'this.GetType().DeclaringMethod' threw an exception of type 'System.InvalidOperationException'
DeclaringType: null
FullName: "QP_Truck.Pages.HandOverListPage"
GenericParameterAttributes: 'this.GetType().GenericParameterAttributes' threw an exception of type 'System.InvalidOperationException'
GenericParameterPosition: 'this.GetType().GenericParameterPosition' threw an exception of type 'System.InvalidOperationException'
GUID: {93eb30b9-a64e-3c6b-9182-0f93582d188d}
HasElementType: false
IsAbstract: false
IsAnsiClass: true
IsArray: false
IsAutoClass: false
IsAutoLayout: true
IsByRef: false
IsClass: true
IsCOMObject: false
IsContextful: false
IsEnum: false
IsExplicitLayout: false
IsGenericParameter: false
IsGenericType: false
IsGenericTypeDefinition: false
IsImport: false
IsInterface: false
IsLayoutSequential: false
IsMarshalByRef: false
IsNested: false
IsNestedAssembly: false
IsNestedFamANDAssem: false
IsNestedFamily: false
IsNestedFamORAssem: false
IsNestedPrivate: false
IsNestedPublic: false
IsNotPublic: false
IsPointer: false
IsPrimitive: false
IsPublic: true
IsSealed: false
IsSerializable: false
IsSpecialName: false
IsUnicodeClass: false
IsValueType: false
IsVisible: true
MemberType: TypeInfo
Module: {QP Truck.exe}
Namespace: "QP_Truck.Pages"
ReflectedType: null
StructLayoutAttribute: {System.Runtime.InteropServices.StructLayoutAttribute}
TypeHandle: {System.RuntimeTypeHandle}
TypeInitializer: null
UnderlyingSystemType: {Name = "HandOverListPage" FullName = "QP_Truck.Pages.HandOverListPage"}
我不確定我是否理解這一點。爲什麼這比'Window.GetWindow'更好的解決方案?你能提供更多的解釋嗎? – 2010-11-17 14:48:04
我並不是說這是更好的解決方案。這只是我解決問題的方式。 – 2010-11-17 14:54:52
我同意 - 頁面沒有魔法所有者,您必須明確設置其所有者。 – 2010-11-17 15:06:07