[英]How to bind wpf UserControl?
我在將viewmodel綁定到我創建的usercontrol時遇到問題。 viewmodel不能反映值的變化。
UpDown.xaml(用戶控件xaml部分)btnUp和btnDown用於更改txtNum的文本。 不知道對不對
<Grid DataContext="{Binding ElementName=btnDownRoot}">
<Grid.RowDefinitions>
<RowDefinition Height="0*"/>
<RowDefinition/>
<RowDefinition Height="0*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0*"/>
<ColumnDefinition Width="78*"/>
<ColumnDefinition Width="104*"/>
<ColumnDefinition Width="77*"/>
<ColumnDefinition Width="0*"/>
</Grid.ColumnDefinitions>
<TextBox Name="txtNum" Text="{Binding ElementName=btnDownRoot, Path=NumValue}" FontSize="20" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" BorderBrush="White" Grid.Column="2" Grid.RowSpan="2"/>
<Button Name="btnUp" Style="{StaticResource ResourceKey=btnUp}" Click="btnUp_Click" Grid.Column="3" Grid.RowSpan="2"/>
<Button Name="btnDown" Style="{StaticResource ResourceKey=btnDown}" Click="btnDown_Click" Grid.RowSpan="2" Grid.ColumnSpan="2"/>
</Grid>
UpDown.xaml.cs(用戶控件代碼部分)
public string NumValue
{
get
{
return GetValue(NumValueProperty).ToString();
}
set
{
SetValue(NumValueProperty, value);
}
}
public static readonly DependencyProperty NumValueProperty =
DependencyProperty.Register("NumValue", typeof(string), typeof(UpDown),
new PropertyMetadata("1", new PropertyChangedCallback(OnNumChanged)));
private static void OnNumChanged(DependencyObject d,DependencyPropertyChangedEventArgs e)
{
var instannce = d.ToString();
}
在MainWindow中,我將MainViewModel綁定到UserControl MainViewModel.cs
public class MainViewModel: BaseViewModel
{
private string _myValue;
public string MyValue
{
get { return _myValue; }
set
{
_myValue = value;
OnPropertyChanged("MyValue");
}
}
}
MainWindow.xaml
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<local:UpDown Grid.Row="0" NumValue="{Binding MyValue}" x:Name="udGuestNum" Width="220" Margin="0 20"/>
<Button Name="btnOK" Grid.Row="1" Content="OK" Click="btnOK_Click"/>
</Grid>
默認情況下,NumValue綁定是OneWay。 要么將其明確設置為TwoWay
NumValue="{Binding MyValue, Mode=TwoWay}"
或將TwoWay設為默認值:
public static readonly DependencyProperty NumValueProperty =
DependencyProperty.Register(
"NumValue", typeof(string), typeof(UpDown),
new FrameworkPropertyMetadata(
"1", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnNumChanged));
數字上/下控制已經開發出來...不要浪費時間,您甚至可以抓取代碼> https://github.com/xceedsoftware/wpftoolkit
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.