[英]Windows Phone Preserving Page State not working
當我轉到另一個頁面時,我試圖保留頁面狀態,但是由於某些原因,當我返回此頁面時,項目將返回其默認狀態。 為什么不起作用? 似乎完美地遵循了教程...
protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedFrom(e);
State["Title"] = TitleTextBox.Text;
//all of those are RadioButtons - if their is a better way to do it then please comment :)
int i = new int();
if (RB0.IsChecked.Value)
i = 0;
else if (RB1.IsChecked.Value)
i = 1;
else if (RB2.IsChecked.Value)
i = 2;
else if (RB3.IsChecked.Value)
i = 3;
State["CheckedRB"] = i;
}
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedTo(e);
if (State.ContainsKey("Title"))
TitleTextBox.Text = State["Title"] as string;
if (State.ContainsKey("CheckedRB"))
{
int i = (int)State["CheckedRB"];
if (i == 0)
RB0.IsChecked = true;
else if (i == 1)
RB1.IsChecked = true;
else if (i == 2)
RB2.IsChecked = true;
else if (i == 3)
RB3.IsChecked = true;
}
}
編輯:我通過添加斷點來跟蹤問題。
protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedFrom(e);
State["Title"] = TitleTextBox.Text;
string look0 = WorkOutName.Text;
string look = State["WorkOutName"] as string;
int i = new int();
if (RB0.IsChecked.Value)
i = 0;
else if (RB1.IsChecked.Value)
i = 1;
else if (RB2.IsChecked.Value)
i = 2;
else if (RB3.IsChecked.Value)
i = 3;
State["CheckedRB"] = i; <-------- breakpoint
結果如下:
(OnNavigatedFrom)
look0 : "Text From TextBox"
look1 : "Text From TextBox"
i : (0, 1, 2, or 3)
與OnNavigatedTo相同:
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedTo(e);
if (State.ContainsKey("Title"))
TitleTextBox.Text = State["Title"] as string; <--breakpoint
if (State.ContainsKey("CheckedRB"))
{
int i = (int)State["CheckedRB"]; <--breakpoint
if (i == 0)
RB0.IsChecked = true;
else if (i == 1)
RB1.IsChecked = true;
else if (i == 2)
RB2.IsChecked = true;
else if (i == 3)
RB3.IsChecked = true;
}
}
並且它們(在OnNavigatedTo上)都沒有熄滅。
我嘗試了您的代碼,它似乎工作正常。 我不知道這是否是您的情況,但請記住,如果應用程序中具有以下導航流程:
Page1 (forward navigation)-> Page2 (back navigation)-> Page1 (forward navigation)-> Page2
如果在第一次訪問時將狀態保存在Page2中,則再次返回Page2時將不會保留該狀態,這是因為進行反向導航時,該頁面將被丟棄,該頁面的狀態字典也將被丟棄。 您可以在文檔中閱讀有關此內容的更多信息。
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