更改当IDataErrorInfo被调用

Question

我想配置我的验证，只有当我点击保存按钮时触发。在开始之前我从来没有使用过IDataErrorInfo我不清楚如何设置它。我正在尝试保留MVVM路径。有什么我可以打电话来手动让我的字段验证点击保存按钮？

实现：

IDataErrorInfo 

文本框XAML：

 Text="{Binding Name, Mode=TwoWay, ValidatesOnDataErrors=True}" />   

代码：

public string Error 
    { 
     get { throw new NotImplementedException(); } 
    } 

    public string this[string columnName] 
    { 
     get 
     { 
      if (columnName == "Name") 
      { 
       if (!Name.Length() >= 6) 
       { 
        return "Name must be 6 chars."; 
       } 
       else 
       { 
        return null; 
       } 
      } 
      return null; 
     } 
    } 

save命令：

private void Save() { 
     //db save, etc.. 
     Need to validate all properity fields 

    } 

Answer 1

我使用IValidateableObject。如果你的对象类实现了这个接口，它暴露你可以覆盖的validate方法，那么你可以只在需要时调用这个验证对象object.validate。它返回true或false。在该验证函数中，您可以循环访问对象属性，并根据您的自定义bunisness逻辑将所需的列添加到IDataerrorInfo中。我通过创建一个由我的模型/对象类继承的Validationbase类来实现此目的。

这里是我的验证基类的例子，你可以继承到模型/对象类：

using Microsoft.VisualBasic; 
using System; 
using System.Collections; 
using System.Collections.Generic; 
using System.Data; 
using System.Diagnostics; 
using System.ComponentModel; 
using System.Collections.Concurrent; 
using System.ComponentModel.DataAnnotations; 
using System.ComponentModel.DataAnnotations.Schema; 

public class ValidationBase : IValidatableObject, IDataErrorInfo, INotifyPropertyChanged 
{ 

     #region "DECLARATIONS" 
     protected Dictionary<string, string> _propertyErrors = new Dictionary<string, string>(); 
     protected List<ValidationResult> _validationResults = new List<ValidationResult>(); 
     public bool HasErrors { 
       get { return (_propertyErrors.Count + _validationResults.Count) > 0; } 
     } 
     #endregion 
     #region "IValidatableObject IMPLEMENTATION" 
     public virtual IEnumerable<ValidationResult> Validate(ValidationContext validationContext) 
     { 
       return null; 
     } 
     #endregion 
     #region "iDataError OBJECTS" 
     //Returns an error message 
     //In this case it is a general message, which is 
     //returned if the list contains elements of errors 
     public string Error { 
       get { 
          if (_propertyErrors.Count > 0) { 
            return "Object data is invalid"; 
          } else { 
            return null; 
          } 
       } 
     } 

     public string this[string columnName] { 
       get { 
          if (_propertyErrors.ContainsKey(columnName)) { 
            return _propertyErrors[columnName].ToString(); 
          } else { 
            return null; 
          } 
       } 
     } 

     #endregion 
     #region "IDataError FUNCTIONS" 
     //Adds an error to the collection, if not already present 
     //with the same key 
     protected void AddError(string columnName, string msg) 
     { 
       if (!_propertyErrors.ContainsKey(columnName)) { 
          _propertyErrors.Add(columnName, msg); 
          OnPropertyChanged(columnName); 
       } 
     } 

     //Removes an error from the collection, if present 
     protected void RemoveError(string columnName) 
     { 
       if (_propertyErrors.ContainsKey(columnName)) { 
          _propertyErrors.Remove(columnName); 
          OnPropertyChanged(columnName); 
       } 
     } 
     public void ClearErrors() 
     { 
       _propertyErrors.Clear(); 
     } 
     #endregion 
     #region "INotifyPropertyChanged IMPLEMENTATION" 
     public event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged; 
     public delegate void PropertyChangedEventHandler(object sender, PropertyChangedEventArgs e); 

     protected virtual void OnPropertyChanged(string propertyName) 
     { 
       if (PropertyChanged != null) { 
          PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
       } 
     } 
     #endregion 

} 

如果您正在使用实体框架模型，我相信validate方法将以前被称为目的是通过db.SaveChanges保存

这里是你如何实现你的模型中validationbase：

using Microsoft.VisualBasic; 
using System; 
using System.Collections; 
using System.Collections.Generic; 
using System.Data; 
using System.Diagnostics; 
public partial class vendor : ValidationBase 
{ 

    #region "PROPERTIES" 
    public bool HasChanges { get; set; } 
    #endregion 

    #region "VALIDATION FUNCTIONS" 

    public override IEnumerable<ComponentModel.DataAnnotations.ValidationResult> Validate(ComponentModel.DataAnnotations.ValidationContext validationContext) 
    { 
     return base.Validate(validationContext); 
     PropertyValitaion(true); 
    } 

    public void PropertyValitaion(bool bAllProperties, string sProperty = "") 
    { 
     //your property specific logic goes here 


    } 
    #endregion 

}