WPF c#中基于INotifyDataErrorInfo的Bool属性更新

在我之前的问题中，我得到了一个如何手动检查验证结果https://stackoverflow.com/questions/39031783/screen-validation-with-data-annotations-on-button-click-in-using-inotifydataerro/39033124#39033124

的解决方案

我有一个模型Person，它包含三个属性FirstName(必需)，MiddleName(可选)和LastName(必需)。

现在我稍微改变了我的代码

public class PersonViewModel : BaseViewModel, INotifyDataErrorInfo {
    private string _personObj = string.Empty;
    public Person PersonObj
    {
        get { return _personObj; }
        set { _personObj= value; OnPropertyChanged(); }
    }
    public bool IsValidObject
    {
        get 
        { 
            var context = new ValidationContext(EmpInfo, null, null);
            bool flag = Validator.TryValidateObject(EmpInfo, context, null, true);
            return flag;
        }
    }
    public ICommand SaveDataCommand
        {
            get
            {
                return new DelegatingCommand(SaveData);
            }
        }
    public void SaveData
        {
            // Validate Data;
        }
}

模型类:Person

public class Person
{
    [Required]
    public string FirstName { get; set; }
    public string MiddleName { get; set; }
    [Required]
    public string LastName { get; set; }
}

My XAML is

<TextBox Text="{Binding PersonObj.FirstName, UpdateSourceTrigger=PropertyChanged,
 ,ValidatesOnNotifyDataErrors=True}" />
<TextBox Text="{Binding PersonObj.MiddleName, UpdateSourceTrigger=PropertyChanged,
 ,ValidatesOnNotifyDataErrors=True}" />
<TextBox Text="{Binding PersonObj.LastName, UpdateSourceTrigger=PropertyChanged,
 ,ValidatesOnNotifyDataErrors=True}" />
<Button Content="Save" IsDefault="True" IsEnabled="{Binding IsValidObject}" Command="{Binding SaveDataCommand}" />

属性IsValidObject最初工作正常。如果我更新FirstName和LastName中的值，那么属性IsValidObject不会更新UI中的结果。

我又用了一个方法

public class PersonViewModel : BaseViewModel, INotifyDataErrorInfo {
    private string _personObj = string.Empty;
    public Person PersonObj
    {
        get { return _personObj; }
        set { _personObj= value; OnPropertyChanged(); }
    }
    public bool IsValidObject
    {
        get 
        { 
            var context = new ValidationContext(EmpInfo, null, null);
            bool flag = Validator.TryValidateObject(EmpInfo, context, null, true);
            return flag;
        }
    }
    public ICommand SaveDataCommand
        {
            get
            {
                return new DelegatingCommand(SaveData, ValidateEmployeeObject);
            }
        }

    public bool ValidateEmployeeObject()
    {
        var context = new ValidationContext(EmpInfo, null, null);
        bool flag = Validator.TryValidateObject(EmpInfo, context, ErrorResult, true);
        return flag;
    }
    public void SaveData
        {
            // Validate Data;
        }
}

这里我介绍了一个方法ValidateEmployeeObject()，它返回TRUE/FALSE，类似于属性IsValidObject。我按照@adminSoftDK在评论部分提出的建议，在 CanExecute SaveDataCommand块中绑定了这个Method。这种方法也失败了…

我如何更新保存按钮使基于上述验证的启用

public PersonViewModel()
{
   SaveDataCommand = new DelegatingCommand(SaveData, ()=> flag);
}
bool flag;
public bool IsValidObject
{
    get 
    { 
        var context = new ValidationContext(EmpInfo, null, null);
        flag = Validator.TryValidateObject(EmpInfo, context, null, true);
        SaveDataCommand.RaiseCanExecute() // don't know what type of command you have but you should have a method which you can call something with Canexecute
        return flag;
    }
}
public bool ValidateEmployeeObject()
{
  return IsValidObject;
}
public ICommand SaveDataCommand { get;  }