ApplicationBarIconButton 为空 [英] ApplicationBarIconButton is null
本文介绍了ApplicationBarIconButton 为空的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
为什么我的 ApplicationBarIconButton 为 null?
Why is my ApplicationBarIconButton null?
<phone:PhoneApplicationPage.ApplicationBar>
<shell:ApplicationBar IsVisible="True" IsMenuEnabled="True" x:Name="appBar">
<shell:ApplicationBarIconButton x:Name="appbarSave"
IconUri="/Icons/appbar.save.rest.png Text="Save" IsEnabled="False"
Click="appbarSave_Click" />
</shell:Application Bar>
</phone:PhoneApplicationPage.ApplicationBar>
appBarSave 对象为空,尝试这个:
The appBarSave object is null, and trying this:
Initialize Component();
appbarSave.IsEnabled = true;
导致 NullReferenceException.该对象唯一起作用的地方是单击事件(如果我启用它):
Results in a NullReferenceException. The only place the object works is in the click event (if I enable it):
private void appbarSave_Click(object sender, EventArgs e)
{
ApplicationBarIconButton button = (ApplicationBarIconButton)sender;
button.IsEnabled = false;
}
我真的希望能够将保存按钮启动为禁用状态并在稍后启用它.
I would really like to be able to start the save button as disabled and enabled it later.
推荐答案
我记得之前遇到过这个问题:有一个解释 此处.一个简单的解决方法是在代码隐藏而不是 xaml 中实例化它(例如 此处).
I remember running into this issue before: there's an explanation here. An easy workaround is just to instantiate it in code-behind rather than xaml (like here).
private ApplicationBarIconButton SaveEdit;
private void InitAppBar()
{
ApplicationBar appBar = new ApplicationBar();
SaveEdit = new ApplicationBarIconButton(new Uri("images/appbar.check.rest.png", UriKind.Relative));
SaveEdit.Click += new EventHandler(OnClick_Check);
SaveEdit.Text = Strings.Save_button;
appBar.Buttons.Add(SaveEdit);
ApplicationBarIconButton CancelEdit = new ApplicationBarIconButton(new Uri("images/appbar.close.rest.png", UriKind.Relative));
CancelEdit.Click += new EventHandler(OnClick_Cancel);
CancelEdit.Text = Strings.Cancel_button;
appBar.Buttons.Add(CancelEdit);
ApplicationBar = appBar;
}
这篇关于ApplicationBarIconButton 为空的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文