[英]How to update multiple instances of user control using MVVM databinding WPF?
I have created a UserControl
with a ProgressBar
and a Label
. 我创建了一个带有
ProgressBar
和Label
的UserControl
。
<Label Content="{Binding ElementName=UserControl, Path=StatusProperty}" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="76,0,0,32" Name="lblStatus" VerticalAlignment="Bottom" Grid.RowSpan="2" />
<ProgressBar Grid.Row="2" Height="20" HorizontalAlignment="Left" Margin="12,3,0,0" Name="pbCheckProgress" Style="{DynamicResource ProgressBarStyle}" Maximum="{Binding ElementName=UserControl, Path=MaximumProperty}" Minimum="{Binding ElementName=UserControl, Path=MinimumProperty}" Value="{Binding ElementName=UserControl, Path=ValueProperty}" VerticalAlignment="Top" Width="156" />
Then I have created the following DependencyProperties
: 然后,我创建了以下
DependencyProperties
:
// Dependency Properties for labels
public static readonly DependencyProperty StatusProperty = DependencyProperty.Register("Status", typeof(string), typeof(UserControl1), new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
// Dependency Properties for progress bar properties
public static readonly DependencyProperty MinimumProperty = DependencyProperty.Register("Minimum", typeof(double), typeof(UserControl1), new FrameworkPropertyMetadata(0.0d, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
public static readonly DependencyProperty MaximumProperty = DependencyProperty.Register("Maximum", typeof(double), typeof(UserControl1), new FrameworkPropertyMetadata(0.0d, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value", typeof(double), typeof(UserControl1), new FrameworkPropertyMetadata(0.0d, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
Now I would like to create multiple instances of this UserControl
in the same page and update the ProgressBar
from code behind using MVVM. 现在,我想在同一页面中创建此
UserControl
多个实例,并使用MVVM从后面的代码更新ProgressBar
。 But I could not figure this out. 但是我无法弄清楚。 Do I need to have a ViewModel for the
UserControl
so that every instance will have its own copy of ViewModel. 我是否需要为
UserControl
使用ViewModel,以便每个实例都有自己的ViewModel副本。
Is there a way to update all the instances from the page ViewModel? 有没有一种方法可以从页面ViewModel更新所有实例?
Thanks & Regards, Bharat 谢谢与问候,巴拉特
If I understand what you correctly, it sounds like you want to create a ViewModel for this UserControl
and then have multiple instances of that ViewModel (one for each instance of the UserControl
on the View). 如果我正确理解您的话,听起来您想为此
UserControl
创建一个ViewModel,然后拥有该ViewModel的多个实例(对于View上每个UserControl
实例,一个实例)。 If you had a single ViewModel with multiple UserControls
bound to it, they would all show exactly the same thing. 如果您有一个ViewModel绑定了多个
UserControls
,则它们都将显示完全相同的内容。
It sounds like you already have a ViewModel for the Page, so you can simply add the ViewModel for the UserControl
as a property of the Page ViewModel, like this: 听起来您已经有了Page的ViewModel,因此您只需将
UserControl
的ViewModel添加为Page ViewModel的属性,如下所示:
public class PageViewModel : INotifyPropertyChanged
{
private UCViewModel _ucViewModel;
//Other ViewModel Code
public UCViewModel UserControlViewModel
{
get { return _ucViewModel; }
}
}
Where UCViewModel is the ViewModel for your UserControl
. 其中UCViewModel是
UserControl
的ViewModel。 Then, in your XAML, you simply bind to the properties on the UCViewModel, like this: 然后,在XAML中,您只需绑定到UCViewModel上的属性,如下所示:
<local:myControl Status="{Binding UserControlViewModel.Status}"... />
If you have a collection of UCViewModels, you'd need to handle it a little differently, but the concept is still the same. 如果您有UCViewModels的集合,则需要以不同的方式处理它,但是概念仍然相同。
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