[英]TextBox in UserControl, can't edit Text dependency property from code behind
My UserControl contains a TextBox and a Button. 我的UserControl包含一个TextBox和一个Button。 The TextBox's Text is correctly populated by a dependency property called X. TextBox的Text由称为X的依赖项属性正确填充。
My Goal: Change the value of X (eg Text of the TextBox) when I press the Button. 我的目标:当我按下按钮时,更改X的值(例如,文本框的文本)。
I have defined the UserControl as follows: 我已经定义了UserControl如下:
<StackPanel Orientation="Horizontal" >
<TextBox Name="Xbox" Text="{Binding Path=X}" Width="50"/>
<Button Content="Current" Click="InsertCurrentBtnClick" />
</StackPanel>
With codebehind: 与代码隐藏:
public double X
{
get { return (double)GetValue(XProperty); }
set { SetValue(XProperty, value); }
}
public static readonly DependencyProperty XProperty =
DependencyProperty.Register("X", typeof(double), typeof(MyUserControl), new PropertyMetadata(0.0));
private void InsertCurrentBtnClick(object sender, RoutedEventArgs e)
{
X = 0.7;
//BindingOperations.GetBindingExpression(this, XProperty).UpdateTarget();
//BindingOperations.GetBindingExpression(Xbox, TextBox.TextProperty).UpdateTarget();
//BindingOperations.GetBindingExpression(Xbox, XProperty).UpdateTarget();
//Xbox.GetBindingExpression(TextBox.TextProperty).UpdateTarget();
//GetBindingExpression(XProperty).UpdateTarget();
}
I have tried several things - one at a time - (see below X=0.7;
) to force the update to the TextBox Text but nothing has helped so far. 我尝试了几件事-一次一件-(请参阅下面的X=0.7;
)来强制更新到TextBox Text,但到目前为止没有任何帮助。
Thanks in advance. 提前致谢。
I'd write it in this way: 我会这样写:
public double X
{
get { return (double)GetValue(XProperty); }
set { SetValue(XProperty, value); }
}
public static readonly DependencyProperty XProperty =
DependencyProperty.Register("X", typeof(double), typeof(MainPage), new PropertyMetadata(new PropertyChangedCallback(Callback)));
public static void Callback(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
(o as MainPage).Xbox.Text = e.NewValue.ToString();
}
private void InsertCurrentBtnClick(object sender, RoutedEventArgs e)
{
X = 0.7;
}
And the xaml code: 和xaml代码:
<StackPanel Orientation="Horizontal" >
<TextBox Name="Xbox" Width="50"/>
<Button Content="Current" Click="InsertCurrentBtnClick" />
</StackPanel>
You need to set the DataContext
for you Control. 您需要为控件设置DataContext
。 As I see X
defined in your control, you need to do this : 正如我在控件中定义的X
,您需要执行以下操作:
public MyUserControl()
{
InitializeComponent();
// add this line
this.DataContext = this;
}
Although, you can bind it as well, just change the xaml: 虽然,您也可以绑定它,但是只需更改xaml:
<UserControl x:Class="SilverlightApplication1.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Name="myWidnow"
d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel Orientation="Horizontal" >
<TextBox Name="Xbox" Width="50" Text="{Binding ElementName=myWidnow, Path=X}" />
<Button Content="Current" Click="InsertCurrentBtnClick" />
</StackPanel>
</Grid>
Notice that I've added the Name proeprty to the UserControl. 请注意,我已将名称属性添加到UserControl。 In this case, you don't have to change anything in the code behid. 在这种情况下,您无需在隐藏的代码中进行任何更改。
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