WPF

Question

我有2个文本字段，代表四边形的Xmin和Xmax值，这些值在myClass的构造函数上初始化。

此外，我还有两个字段Delta和Counter，这些字段取决于Xmin和Xmax，必须使用公式进行更新：

this.Delta = (int)((this.Xmax - this.Xmin) / (this.Counter - 1));

和

this.Counter = ((this.Xmax - this.Xmin) / (this.Delta)) + 1 ;

这似乎并不那么困难，但我想允许Delta和Counter更新，如果有其他更改，即如果Delta更改，那么Counter更新，反之亦然，所有这些考虑Xmin和Xmax值

这是我所拥有的

WPF

<GroupBox Header="Values" Height="93" HorizontalAlignment="Left" Margin="4,3,0,0" Name="GBoxGridDefinition" VerticalAlignment="Top" Width="624">
<Grid>
    <TextBlock Height="20"  Margin="20,13,0,0" Name="TbXmin" Text="Xmin:"  Width="36" />                        
    <controls:WaterMarkNumericInput x:Name="TBXmin" Height="20" Width="89"   Margin="59,9,0,0" Style="{StaticResource goStRWMNI}" Number="{Binding Path=Xmin, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True,NotifyOnValidationError=True}" IsNullAllowed="False" />
    <TextBlock Height="20"  Margin="154,10,0,0" Name="TbXmax" Text="Xmax:"  Width="36" />                        
    <controls:WaterMarkNumericInput x:Name="TBXmax" Height="20" Width="89"   Margin="198,10,0,0" Style="{StaticResource goStRWMNI}" Number="{Binding Path=Xmax, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True,NotifyOnValidationError=True}" IsNullAllowed="False" />
</Grid>
</GroupBox>
<GroupBox Header="Dynamic changes" Height="77" HorizontalAlignment="Left" Margin="5,98,0,0" Name="GbxNodes" VerticalAlignment="Top" Width="463" >
<Grid>
    <TextBlock Height="20"  Margin="28,7,0,0" Name="TbDelta" Text="Delta X:"  Width="48" />                        
    <controls:WaterMarkNumericInput x:Name="TBDelta" Height="20" Width="119"   IsNegativeSignAllowed="False" Margin="90,4,0,0" Style="{StaticResource goStRWMNI}" Number="{Binding Path=Delta, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True, NotifyOnValidationError=True}" IsNullAllowed="False"/>
    <TextBlock Height="20"  Margin="223,6,0,0" Name="TbCounter" Text="XX' nodes counter:"  Width="109" />
    <controls:WaterMarkNumericInput x:Name="TBCounter" IsEnabled="False" Height="20" Width="111"   Margin="330,4,0,0" Style="{StaticResource goStRWMNI}" Number="{Binding Path=Counter, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True,NotifyOnValidationError=True}" IsNullAllowed="False" />
</Grid>
</GroupBox>

我添加了绑定和属性更改，在开头Counter = 100，但我不知道在Counter更改时如何更新Delta而反之亦然

这是c＃代码

public partial class myClass : UserControl
{
    double gnXmin, gnXmax, gnCounter;
    int gnDelta;
    public event PropertyChangedEventHandler PropertyChanged;
    public double Xmin
    {
        get { return gnXmin; }
        set { gnXmin = value;  OnPropertyChanged("Xmin"); }
    }
    public double Xmax
    {
        get { return gnXmax; }
        set { gnXmax = value; OnPropertyChanged("Xmax");  }
    }
    public int Delta
    {
        get { return gnDelta; }
        set { gnDelta = value; OnPropertyChanged("Delta"); }
    }
    public double Counter
    {
        get { return gnCounter; }
        set { gnCounter = value; OnPropertyChanged("Counter"); }
    }
    public myClass(double _Xmin, double _Xmax)
    {
        this.Xmin  = _Xmin;
        this.Xmax = _Xmax;
        this.Counter  = 100;
        this.Delta = (int)((this.Xmax - this.Xmin) / (this.Counter - 1));
    }
    void OnPropertyChanged(string prop)
    {
        if (this.PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(prop));
    }

}

如何更新这两个元素或绑定它们，以便在修改其他元素时修改每个元素，但考虑Xmin和Xmax属性？

我尝试将更新代码放在getter和setter中，但是因为一个字段依赖于Xmin和Xmax我得到一个无限循环异常......

Answer 1

回答这个问题＆＃34;如何在Delta改变时更新计数器，反之亦然？＃34; 更改Delta值时通知计数器，并在计数器更改时通知Delta。如果这个解决方案没有帮助，请告诉我

public int Delta
    {
        get { return gnDelta; }
        set { gnDelta = value; 
              OnPropertyChanged("Delta"); 
              OnPropertyChanged("Counter");}
    }
    public double Counter
    {
        get { return gnCounter; }
        set { gnCounter = value; 
            OnPropertyChanged("Counter");
            OnPropertyChanged("Delta"); }
    }

Answer 2

为了避免无限循环，在执行任何其他操作之前，请确保传递的value确实与setter中的当前值不同：

public double Counter
{ 
    get { ... }
    set 
    {
        if (gnCounter != value)
        {  
            gnCounter = value;
            Delta = (int)((Xmax - Xmin) / (gnCounter  - 1));
            OnPropertyChanged("Counter");
        } 
    }
}

当然，您必须对Delta属性执行相同操作。

根据每个其他值更新2个字段，但每个字段还取决于其他属性值

WPF

2 个答案: