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我正在尝试使用计算出的列在我的网格中显示。

我有一个由 EF 代码生成器自动生成的具有三个属性的部分类：我正在尝试创建另一个部分类并在那里添加计算字段，例如

Public partial class Employee
{
public decimal? totalSalary
{
get

{
return salary*wagerate+bonus;
}
}
}

它第一次可以正常工作，但在薪水/奖金/工时更改时不起作用。我在网格中使用这些字段

这是我由 EF 实体生成器生成的代码

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated from a template.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Globalization;
using System.Runtime.Serialization;
using System.ComponentModel.DataAnnotations;

namespace Employees.Contract
{
[DataContract(IsReference = true)]
[KnownType(typeof(Department))]
[KnownType(typeof(PropertyType))]
public partial class Employee: IObjectWithChangeTracker, INotifyPropertyChanged,IDataErrorInfo
{

    [NonSerialized]
    private CLOS.Contract.Validation.DataErrorInfoSupport dataErrorInfoSupport;

    public Employee()
    {            
        dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
        Init();
    }

    partial void Init();

    string IDataErrorInfo.Error { get { return dataErrorInfoSupport.Error; } }

    string IDataErrorInfo.this[string memberName] { get { return dataErrorInfoSupport[memberName]; } }

    #region Primitive Properties


    [DataMember]
    public Nullable<decimal> Salary
    {
        get { return _salary; }
        set
        {
            if (_salary != value)
            {
                _salary = value;
                OnPropertyChanged("Salary");
            }
        }
    }
    private Nullable<decimal> _salary;

    [DataMember]
    public Nullable<decimal> WageRate
    {
        get { return _wageRate; }
        set
        {
            if (_wageRate != value)
            {
                _wageRate = value;
                OnPropertyChanged("WageRate");
            }
        }
    }
    private Nullable<decimal> _wageRate;

    [DataMember]
    public Nullable<decimal> Bonus
    {
        get { return _bonus; }
        set
        {
            if (_bonus != value)
            {
                _bonus = value;
                OnPropertyChanged("Bonus");
            }
        }
    }
    private Nullable<decimal> _bonus;

    #endregion
    #region Navigation Properties

    [DataMember]
    public Department Department
    {
        get { return _department; }
        set
        {
            if (!ReferenceEquals(_department, value))
            {
                var previousValue = _department;
                _department = value;
                OnNavigationPropertyChanged("Department");
            }
        }
    }
    private Borrower _department;

    [DataMember]
    public PropertyType PropertyType
    {
        get { return _propertyType; }
        set
        {
            if (!ReferenceEquals(_propertyType, value))
            {
                var previousValue = _propertyType;
                _propertyType = value;

                OnNavigationPropertyChanged("PropertyType");
            }
        }
    }
    private PropertyType _propertyType;

    #endregion
    #region ChangeTracking

    protected virtual void OnPropertyChanged(String propertyName)
    {
        if (ChangeTracker.State != ObjectState.Added && ChangeTracker.State != ObjectState.Deleted)
        {
            ChangeTracker.State = ObjectState.Modified;
        }
        if (_propertyChanged != null)
        {
            _propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    protected virtual void OnNavigationPropertyChanged(String propertyName)
    {
        if (_propertyChanged != null)
        {
            _propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged{ add { _propertyChanged += value; } remove { _propertyChanged -= value; } }
    private event PropertyChangedEventHandler _propertyChanged;
    private ObjectChangeTracker _changeTracker;

    [DataMember]
    public ObjectChangeTracker ChangeTracker
    {
        get
        {
            if (_changeTracker == null)
            {
                _changeTracker = new ObjectChangeTracker();
                _changeTracker.ObjectStateChanging += HandleObjectStateChanging;
            }
            return _changeTracker;
        }
        set
        {
            if(_changeTracker != null)
            {
                _changeTracker.ObjectStateChanging -= HandleObjectStateChanging;
            }
            _changeTracker = value;
            if(_changeTracker != null)
            {
                _changeTracker.ObjectStateChanging += HandleObjectStateChanging;
            }
        }
    }

    private void HandleObjectStateChanging(object sender, ObjectStateChangingEventArgs e)
    {
        if (e.NewState == ObjectState.Deleted)
        {
            ClearNavigationProperties();
        }
    }

    protected bool IsDeserializing { get; private set; }

    [OnDeserializing]
    public void OnDeserializingMethod(StreamingContext context)
    {
        IsDeserializing = true;
    }

    [OnDeserialized]
    public void OnDeserializedMethod(StreamingContext context)
    {
        dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
        IsDeserializing = false;
        ChangeTracker.ChangeTrackingEnabled = true;
    }

    protected virtual void ClearNavigationProperties()
    {
        Department = null;
        PropertyType = null;
    }

    #endregion
}

}

如果我OnPropertyChanged("Salary")在 EF Generated 类中输入 Hours,Wage,Overtime 属性（这不是一个好主意），它也可以工作，因为如果类重新生成，我的代码将被清除

任何帮助表示赞赏。（对不起格式，这是我的第一个问题）

谢谢

4

2 回答 2

1

In the partial class use the partial Init method to subscribe to the PropertyChanged event and when either the salary, wagerate or bonus property changes notify clients of the change of the totalSalary.

This way you do not need to modify the generated code. (that is why the Init method is partial). 

public partial class Employee
{

    partial void Init()
    {
        _propertyChanged += PropertyChangedHandler;
    }

    void PropertyChangedHandler(object sender, PropertyChangedEventArgs args)
    {
        if(args.PropertyName == "salary" ||
           args.PropertyName == "wagerate" ||
           args.PropertyName == "bonus")
         {
             OnPropertyChanged("totalSalary");
         }
    }

    public decimal? totalSalary
    {
        get
        {
            return salary * wagerate + bonus;
        }
    }
}
于 2013-01-14T06:09:57.420 回答
0

这就是为什么 MVVM 是一种流行的设计模式的原因，如果你将你的 Employee（一个模型）包装在一个新的类（一个 ViewModel）中，在你把它交给网格（视图）之前定制会更容易。

但是，让当前代码正常工作的一种巧妙方法是附加到部分类中的当前 PropertyChanged 事件，并OnPropertyChanged("Salary")在当前属性名称与依赖属性之一匹配时调用（注意递归！）

于 2013-01-14T02:44:03.717 回答