Question

在我以前的问题中，我得到了一个解决方案，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

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

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;
        }

}

模特类：人

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

    public string MiddleName { get; set; }

    [Required]
    public string LastName { get; set; }
}

我的XAML

<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最初可以正常工作。如果我更新FirstName和LastName中的值，则属性IsValidObject不会在UI中更新结果。

我又使用了一种方法

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;
        }

}

我在这里介绍了一种方法ValidateEmployeeObject()，它返回TRUE / FALSE，类似于属性IsValidObject。我在@adminSoftDK在评论部分中提出的 CanExecute SaveDataCommand块中绑定了此方法。这种方法也失败了......

如何根据上述验证更新“保存”按钮以启用“启用”。

Answer 1

如果你尝试这样的话

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;  }

我对INotifyDataErrorInfo不是很熟悉，我不知道你的IsValidObject被调用到什么时候，但我认为上面的内容应该有效。

在WPF C＃

1 个答案: