CustomValidation属性似乎不工作 [英] CustomValidation attribute doesn't seem to work
问题描述
我有一个简单的测试页面中，我试图让一个自定义的验证规则，以便我的Silverlight 4应用程序。
我有一个文本框和一个按钮，我显示一个TextBlock验证结果。我的观点模型有一个名称属性，这势必TextBox的Text属性。我对Name属性两个验证属性， [必需] 和 [CustomValidation] 。
当我打的提交按钮，所需要的验证火灾正确的，但我的自定义验证程序的验证方法从来没有被击中里面的断点。我不明白这是为什么，因为我觉得我非常小心地遵循MS的例子：的 http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.customvalidationattribute（v = VS.95）的.aspx
下面是视图模型的代码：
使用系统;
使用System.Collections.Generic;使用System.ComponentModel.DataAnnotations
;
使用System.Linq的;
使用GalaSoft.MvvmLight.Command;
命名空间MyProject的
{
//自定义的验证类
公共类StartsCapitalValidator
{
公共静态的ValidationResult的IsValid（字符串值）
{
//此代码永远不会被击中
如果（value.Length大于0）
{
VAR有效=（值[0]的ToString（）==值[0]的ToString（）ToUpper的（））。 （！有效）
如果
返回新的ValidationResult（名称必须以大写字母开头）;
}
返回ValidationResult.Success;
}
}
//我的视图模型
公共类ValidationTestViewModel：ViewModelBase
{
//属性进行验证
字符串_name;
[必填]
[CustomValidation（typeof运算（StartsCapitalValidator）的IsValid）]
公共字符串名称
{
{返回_name; }
集合{的SetProperty（REF _name，价值，（）=>名称）; }
}
串_result;
公共字符串结果
{
{返回_result; }
私人集合{的SetProperty（REF _result，价值，（）=>结果）; }
}
公共RelayCommand SubmitCommand {搞定;私人集; }
公共ValidationTestViewModel（）
{
SubmitCommand =新RelayCommand（提交）;
}
无效提交（）
{
//执行验证，当用户点击提交按钮
VAR误差=新的List<为ValidationResult>（ ）;
如果（！Validator.TryValidateObject（这一点，新ValidationContext（本，NULL，NULL），错误））
{
//我们永远只能到这里从所需验证，永远不会从的CustomValidator
结果=的String.Format（{0}个错误：\\\
{1}，
errors.Count，
的string.join（\\\
errors.Select（E => e.ErrorMessage）））;
}
，否则
{
结果=有效;
}
}
}
}
下面认为：
<导航：第x页：类=Data.Byldr.Application.Views.ValidationTest
的xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
的xmlns：X =http://schemas.microsoft.com/winfx/2006/xaml
的xmlns：D =http://schemas.microsoft.com/expression/blend/2008
的xmlns：MC =http://schemas.openxmlformats.org/markup-compatibility/2006
的xmlns：导航=CLR的命名空间：System.Windows.Controls;装配= System.Windows.Controls.Navigation>
<电网WIDTH =400>
<&StackPanel的GT;
<文本框的文本={绑定名称，模式=双向}/>
<按钮命令={结合SubmitCommand}CONTENT =提交/>
< TextBlock的文本={结合}的结果/>
< / StackPanel的>
< /网格和GT;
< /导航：第>
至于那超负荷的MSDN页面上注明 Validator.TryValidateObject （ HTTP ：//msdn.microsoft.com/en-us/library/dd411803（v = VS.95）的.aspx 的），只有对象级验证用这种方法检查，并且RequiredAttribute标签上的属性
要查看属性级别的验证，使用重载，还需要一个布尔（的 http://msdn.microsoft.com/en-us/library/dd411772（v = VS.95）的.aspx ）
所以应该是传递真作为一个额外的参数 TryValidateObject
那么简单
I have a simple test page in my Silverlight 4 application in which I'm trying to get a custom validation rule to fire.
I have a TextBox and a Button, and I am showing the validation results in a TextBlock. My view model has a Name property, which is bound the the Text property of the TextBox. I have two validation attributes on the Name property, [Required] and [CustomValidation].
When I hit the Submit button, the Required validator fires correctly, but the breakpoint inside the validation method of my custom validator never gets hit. I can't see why this is, as I think I have followed MS's example very carefully: http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.customvalidationattribute(v=vs.95).aspx
Here is the code for the view model:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using GalaSoft.MvvmLight.Command;
namespace MyProject
{
// custom validation class
public class StartsCapitalValidator
{
public static ValidationResult IsValid(string value)
{
// this code never gets hit
if (value.Length > 0)
{
var valid = (value[0].ToString() == value[0].ToString().ToUpper());
if (!valid)
return new ValidationResult("Name must start with capital letter");
}
return ValidationResult.Success;
}
}
// my view model
public class ValidationTestViewModel : ViewModelBase
{
// the property to be validated
string _name;
[Required]
[CustomValidation(typeof(StartsCapitalValidator), "IsValid")]
public string Name
{
get { return _name; }
set { SetProperty(ref _name, value, () => Name); }
}
string _result;
public string Result
{
get { return _result; }
private set { SetProperty(ref _result, value, () => Result); }
}
public RelayCommand SubmitCommand { get; private set; }
public ValidationTestViewModel()
{
SubmitCommand = new RelayCommand(Submit);
}
void Submit()
{
// perform validation when the user clicks the Submit button
var errors = new List<ValidationResult>();
if (!Validator.TryValidateObject(this, new ValidationContext(this, null, null), errors))
{
// we only ever get here from the Required validation, never from the CustomValidator
Result = String.Format("{0} error(s):\n{1}",
errors.Count,
String.Join("\n", errors.Select(e => e.ErrorMessage)));
}
else
{
Result = "Valid";
}
}
}
}
Here is the view:
<navigation:Page x:Class="Data.Byldr.Application.Views.ValidationTest"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation">
<Grid Width="400">
<StackPanel>
<TextBox Text="{Binding Name, Mode=TwoWay}" />
<Button Command="{Binding SubmitCommand}" Content="Submit" />
<TextBlock Text="{Binding Result}" />
</StackPanel>
</Grid>
</navigation:Page>
As stated on the MSDN page for that overload of Validator.TryValidateObject ( http://msdn.microsoft.com/en-us/library/dd411803(v=VS.95).aspx ), only the object-level validations are checked with this method, and RequiredAttribute on properties.
To check property-level validations, use the overload that also takes a bool ( http://msdn.microsoft.com/en-us/library/dd411772(v=VS.95).aspx )
So it should be as simple as passing "true" as an extra parameter to TryValidateObject
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