如何解决WPF4 / C#-System.StackOverflowException崩溃应用程序
|| 在下面,您可以看到我的.xaml.cs代码。该应用程序可以正常打开。用户可以更改4个文本框。当您在文本框中编辑默认值之一,然后单击以取消选择默认值时,应用程序崩溃,并显示System.StackOverflowException错误,并说我在get {}或Calc()函数上存在无限循环或递归,取决于要编辑的文本框。我希望应用程序每次不编辑文本框时都根据Calc()函数计算数字。我还想为文本框定义一些起始值,但是还没有弄清楚该怎么做。 有什么想法可以解决循环错误和初始值定义吗? .xaml代码中的文本框遵循以下模式:Text=\"{Binding DistanceBox}\"
完整的后台代码如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.ComponentModel;
namespace ConverterApp
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new Variables();
}
}
public class Variables : INotifyPropertyChanged
{
// Declare the PropertyChanged event.
public event PropertyChangedEventHandler PropertyChanged;
private double m_distanceBox;
public double DistanceBox
{
get { return m_distanceBox; }
set
{
//If value hasn\'t changed,don\'t do anything
//if (m_distanceBox == value)
// return;
m_distanceBox = value;
// modify calc to read the text values
Calc();
// Call NotifyPropertyChanged when the source property
// is updated.
//if(PropertyChanged!= null)
NotifyPropertyChanged(\"DistanceBox\");
}
}
private double m_widthBox;
public double WidthBox
{
get { return m_widthBox; }
set
{
m_widthBox = value;
// modify calc to read the text values
Calc();
// Call NotifyPropertyChanged when the source property
// is updated.
NotifyPropertyChanged(\"WidthBox\");
}
}
private double m_lengthBox;
public double LengthBox
{
get { return m_lengthBox; }
set
{
m_lengthBox = value;
// modify calc to read the text values
Calc();
// Call NotifyPropertyChanged when the source property
// is updated.
NotifyPropertyChanged(\"LengthBox\");
}
}
private double m_lensBox;
public double LensNeeded
{
get { return m_lensBox; }
set
{
m_lensBox = value;
// modify calc to read the text values
Calc();
// Call NotifyPropertyChanged when the source property
// is updated.
NotifyPropertyChanged(\"LensNeeded\");
}
}
public void Calc()
{
double WidthBased = 2.95 * (DistanceBox / WidthBox);
double LengthBased = 3.98 * (DistanceBox / LengthBox);
if (WidthBased < LengthBased)
{
LensNeeded = Math.Round(WidthBased,2);
}else{
LensNeeded = Math.Round(LengthBased,2);
}
}
// NotifyPropertyChanged will raise the PropertyChanged event,// passing the source property that is being updated.
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,new PropertyChangedEventArgs(propertyName));
}
}
}
}
解决方法
在
LensNeeded
的设置器中,您叫Calc
,calc依次设置LensNeeded
,LensNeeded
的设置器则叫Calc
,依此类推。这种循环性导致StackOverflow。
不要在这样的setter中计算属性,而是将各个属性设置为“ virtual”(虚拟)(即时计算值,而不是从备用字段获取值),例如
public double WidthBased
{
get { return 2.95 * (DistanceBox / WidthBox); }
}
要更新与这些属性的绑定,可以在所有相关属性的设置器中引发属性更改的事件,这里是DistanceBox
和WidthBox
的设置器。
private double m_distanceBox;
public double DistanceBox
{
get { return m_distanceBox; }
set
{
if (m_distanceBox != value)
{
m_distanceBox = value;
NotifyPropertyChanged(\"DistanceBox\");
NotifyPropertyChanged(\"WidthBased\");
}
}
}
初始值可以在变量类的构造函数中设置,也可以直接在字段声明中设置,例如
private double m_distanceBox = 10;
public double DistanceBox //...
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