限制WPF中元素的移动

Question

如何限制元素的移动?

一旦我在TextBox中为元素的位置(x, y值)写了一个值，对象就会移动到那个位置。

我想限制移动，例如:AuslegerProzess(元素名)最大位置移动x = 480，最小位置移动x = 375，并且我可以将它移动到375和480之间的位置。

**这是我的XAML: **

d:DesignHeight="600" d:DesignWidth="1000">
<Canvas x:Name="canvas" Margin="0,0,-163,-83">
<Path x:Name="AuslegerProzess" Fill="#FFB3B3B3" StrokeThickness="1.6705512" Stroke="#FF000000" StrokeMiterLimit="4" Data="M 178.83594 375.22266 L 178.83594 382.85742 L 168.51172 382.85742 L 168.51172 389.43555 L 163.51172 389.43555 L 163.51172 432.69531 L 168.51172 432.69531 L 168.51172 448.57227 L 178.83594 448.57227 L 178.83594 466.27344 L 178.83594 471.98242 L 150.82031 471.98242 L 150.82031 480.24805 L 136.57812 480.24805 L 136.57812 564.00391 L 331.24805 564.00391 L 331.24805 480.24805 L 317.60742 480.24805 L 317.60742 471.98242 L 291.99023 471.98242 L 291.99023 466.27344 L 291.99023 448.57227 L 701.44531 448.57227 L 701.44531 382.85742 L 291.99023 382.85742 L 291.99023 375.22266 L 178.83594 375.22266 z " Canvas.Left="{Binding PositionX, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Canvas.Top="{Binding PositionY, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Height="133.144" Stretch="Fill" Width="663.163" >
<Path.RenderTransform>
<TransformGroup>
<ScaleTransform ScaleY="0.265" ScaleX="0.265"/>
<SkewTransform/>
<RotateTransform/>
<TranslateTransform/>
</TransformGroup>
</Path.RenderTransform>
</Path>
<Path x:Name="ClampRechts" Fill="#FF000000" StrokeThickness="2.12787" Data="M 524.2207 473.57227 L 524.2207 563.57227 L 137.14258 563.57227 L 137.14258 652.14258 L 571.42773 652.14258 L 571.42773 563.57227 L 571.36328 563.57227 L 571.36328 473.57227 L 524.2207 473.57227 z " Height="68.929" Stretch="Fill" Width="79.7" Canvas.Left="411.15" Canvas.Top="339.369">
<Path.RenderTransform>
<TransformGroup>
<ScaleTransform ScaleY="0.265" ScaleX="0.265"/>
<SkewTransform/>
<RotateTransform/>
<TranslateTransform/>
</TransformGroup>
</Path.RenderTransform>
</Path>
<Path x:Name="ClampLinks"  Fill="#FF000000" StrokeThickness="2.12787" Data="M 110 344.28516 L 110 434.28516 L 110 485.71484 L 110 522.85742 L 544.28516 522.85742 L 544.28516 434.28516 L 157.14258 434.28516 L 157.14258 344.28516 L 110 344.28516 z " Height="68.668" Stretch="Fill" Width="80.733" Canvas.Left="377.134" Canvas.Top="339.499">
<Path.RenderTransform>
<TransformGroup>
<ScaleTransform ScaleY="0.265" ScaleX="0.265"/>
<SkewTransform/>
<RotateTransform/>
<TranslateTransform/>
</TransformGroup>
</Path.RenderTransform>
</Path>
<Rectangle Canvas.Left="735" Width="150" Height="449" x:Name="rect10_Copy" Fill="#FFB3B3B3" StrokeThickness="0.264583" Canvas.Top="74"/>

<TextBox Height="30" Canvas.Left="109" TextWrapping="Wrap" Canvas.Top="260" Width="120" FontSize="20" Text="{Binding PositionX, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"/>
<Label Content="X Position" Canvas.Left="14" Canvas.Top="262" FontWeight="Bold" FontSize="15"/>
<Label Content="Ausleger Prozess" Canvas.Left="10" Canvas.Top="218" FontWeight="Bold" FontSize="20" Height="38" Width="180"/>


<TextBox Name="TxtBoxY" Height="30" Canvas.Left="105" TextWrapping="Wrap" Canvas.Top="142" Width="120" FontSize="20" Text="{Binding PositionY, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" UndoLimit="600"/>
<Label Content="Y Position" Canvas.Left="10" Canvas.Top="142" FontWeight="Bold" FontSize="15"/>
<Button Content="START" Canvas.Left="84" Canvas.Top="403" Width="106" Height="48" FontSize="30" FontWeight="Bold" Name="BtnStart" Command="{Binding ClickCommand, UpdateSourceTrigger=PropertyChanged}"/>

<Path Name="Lift" Fill="#FF808080" Data="m 67.621819 110.44866 v 16.55811 H 176.13074 v -16.55811 z m 0.143117 16.70929 v 1.59777 h 0.743496 v 4.86682 h 18.534155 v -4.86682 H 140.4094 v 4.84489 h 18.53416 v -4.84489 h 17.04716 v -1.59777 z m 93.167904 1.59774 c 0.10872 56.40049 0.026 57.01222 0.026 57.01222 l 15.18908 17.62703 -0.005 -74.7721 -15.21024 0.13288" Canvas.Left="549" Canvas.Top="{Binding PositionY, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Height="135.111" Stretch="Fill" Width="185.378"/>
<Label Content="LIFT" Canvas.Left="10" Canvas.Top="101" FontWeight="Bold" FontSize="20" Height="36" Width="52"/>
</Canvas>
<UserControl.DataContext>
<viewmodel:ProzessViewModel/>
</UserControl.DataContext>
</UserControl>

这是我的ViewModel:

public class ProzessViewModel : BaseViewModel
{
private ICommand _clickCommand;
private double _positionX = 375;
private double _positionY = 303.707;


public double PositionX
{
get { return _positionX; }
set
{
_positionX = value;
RaisePropertyChanged("PositionX");

}
}
public double PositionY
{
get { return _positionY; }
set
{
_positionY = value;
RaisePropertyChanged("PositionY");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string property)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(property));
}
}

public ICommand ClickCommand { get; set; }

我在网上搜索，我找到了一些例子，但它不起作用。

Answer 1

你可以在PositionX上添加你的条件

public double PositionX
{
get { return _positionX; }
set
{
if(value >= 375 && value <= 480)// put an necessary condition here
{
_positionX = value;
RaisePropertyChanged("PositionX");
}
}
}

编辑:关于你的评论，问题是你有一个UpdateSourceTrigger=PropertyChanged在你的文本框，所以绑定将更新PositionX每次你编辑复选框中的文本。最简单的方法是去除UpdateSourceTrigger=PropertyChanged。如果你想保持它(立即改变位置，而不离开TextBox)，你需要定义第二个参数:

PositionX1是你绑定TextBox的位置，它会在每次你编辑CheckBox时被改变(当然你需要检查用户没有在里面放一些文本)。

public double PositionX1
{
get { return _positionX1; }
set
{
{
_positionX = value;
PositionX2 = _positionX;
RaisePropertyChanged("PositionX1");
}
}
}

PositionX2是用来绑定画布的

public double PositionX2
{
get { return _positionX2; }
set
{
if(value >= 375 && value <= 480)// put an necessary condition here
{
_positionX = value;
RaisePropertyChanged("PositionX2");
}
}
}

就像这样，只有当你的文本框中的值在375到480之间时，PositionX2才会更新。