Silverlight ValidationSummary不显示异常的小问题

这两天在做Silverlight输入验证时想使用Silverlight的控件验证及ValidationSummary，但发现控件能根据Model进行验证，但ValidationSummary总不能显示汇总的错误信息，原来是xaml文件中ValidationSummary控件与Grid控件之间放了一个stackPanel导致ValidationSummary不能正常显示验证的汇总信息，将StackPanel删除掉，将ValidationSummary控件作为Grid的直接子元素就行了。下面贴上代码。

首先是错误的xaml代码

<Grid Name="gridProductDetails" Background="White" >
        <Grid.ColumnDeFinitions>
            <ColumnDeFinition Width="Auto"></ColumnDeFinition>
            <ColumnDeFinition></ColumnDeFinition>
        </Grid.ColumnDeFinitions>
        <Grid.RowDeFinitions>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="*"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
        </Grid.RowDeFinitions>

        <TextBlock Margin="7">Model Number:</TextBlock>
        <TextBox Margin="5" Grid.Column="1" Width="100" HorizontalAlignment="Left" x:Name="txtModelNumber" 
   Text="{Binding ModelNumber,Mode=TwoWay,ValidatesOnExceptions=True,NotifyOnValidationError=True}"></TextBox>
        <TextBlock Margin="7" Grid.Row="1">Model Name:</TextBlock>
        <TextBox Margin="5" Grid.Row="1" Grid.Column="1"
   Text="{Binding ModelName,TargetNullValue='[this is null]',NotifyOnValidationError=True}"></TextBox>
        <TextBlock Margin="7" Grid.Row="2">Unit Cost:</TextBlock>
        <TextBox Margin="5" Grid.Row="2" Grid.Column="1" x:Name="txtUnitCost" Width="100" HorizontalAlignment="Left"
   Text="{Binding UnitCost,Mode=TwoWay}"></TextBox>
        <TextBlock Margin="7,7,0" Grid.Row="3">Description:</TextBlock>
        <TextBox Margin="5" Grid.Row="3" Grid.Column="1"
   Text="{Binding ModelName2,FallbackValue='N/A load Failed'}"></TextBox>
        <TextBox Margin="7,9" Grid.Row="4" Grid.ColumnSpan="2"
   Text="{Binding Description,Mode=TwoWay}" textwrapping="Wrap"></TextBox>

        
        <StackPanel Margin="7" Grid.Row="5" Grid.ColumnSpan="2">
            <TextBlock>汇总验证信息：</TextBlock>
        <sdk:ValidationSummary x:Name="validationSummary" MinHeight="50" />
        <!--注意，必须将ValidationSummary放在Grid的下一级，不能在ValidationSummary和Grid间加上其他容器控件，否则不触发-->
        </StackPanel>
        <TextBlock  Margin="7" Grid.Row="6" Grid.ColumnSpan="2" Foreground="Red" FontWeight="Bold" x:Name="lblInfo" ></TextBlock>
        
        <Button Grid.Row="7" x:Name="btnCheck" Click="btnCheck_Click">测试</Button>
    </Grid>

再是正确的xaml代码

<Grid Name="gridProductDetails" Background="White" >
        <Grid.ColumnDeFinitions>
            <ColumnDeFinition Width="Auto"></ColumnDeFinition>
            <ColumnDeFinition></ColumnDeFinition>
        </Grid.ColumnDeFinitions>
        <Grid.RowDeFinitions>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="*"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
            <RowDeFinition Height="Auto"></RowDeFinition>
        </Grid.RowDeFinitions>

        <TextBlock Margin="7">Model Number:</TextBlock>
        <TextBox Margin="5" Grid.Column="1" Width="100" HorizontalAlignment="Left" x:Name="txtModelNumber" 
   Text="{Binding ModelNumber,Mode=TwoWay}" textwrapping="Wrap"></TextBox>

        
        <sdk:ValidationSummary x:Name="validationSummary" MinHeight="50" Margin="7" Grid.Row="5" Grid.ColumnSpan="2"/>
        <!--注意，必须将ValidationSummary放在Grid的下一级，不能在ValidationSummary和Grid间加上其他容器控件，否则不触发-->
        <TextBlock  Margin="7" Grid.Row="6" Grid.ColumnSpan="2" Foreground="Red" FontWeight="Bold" x:Name="lblInfo" ></TextBlock>
        
        <Button Grid.Row="7" x:Name="btnCheck" Click="btnCheck_Click">测试</Button>
    </Grid>

正确的后台代码

public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
        }

        private void UserControl_Loaded(object sender,RoutedEventArgs e)
        {
            //方式1，通过后台代码设置数据源

            Product product = new Product("AEFS100","Portable",77,"Analyzes the electrical activity of a person's heart and applies " +
"an electric shock if necessary.");
            gridProductDetails.DataContext = product;
            validationSummary.DataContext = product;


        }

        private void btnCheck_Click(object sender,RoutedEventArgs e)
        {
            Product product= gridProductDetails.DataContext as Product;
            lblInfo.Text = "Model Name: " + product.ModelName + "\nModel Number: " +
product.ModelNumber + "\nUnit Cost: " + product.UnitCost;
        }
    }

public class Product
    {
        private string modelNumber;
        [StringLength(25)]
        [required(ErrorMessage="型号是必填字段")]
        public string ModelNumber
        {
            get { return modelNumber; }
            set {
                //if (value==null || string.IsNullOrEmpty(value.ToString())) 
                //{
                //    throw new Exception("抛出异常，型号是必填字段");
                //}
                ValidationContext context = new ValidationContext(this,null,null);
                context.MemberName = "ModelNumber";
                Validator.ValidateProperty(value,context);

                modelNumber = value; }
        }
        private string modelName;
        [StringLength(26)]
        [required()]
        public string ModelName
        {
            get { return modelName; }
            set 
            {
                ValidationContext context = new ValidationContext(this,null);
                context.MemberName = "ModelName";
                Validator.ValidateProperty(value,context);

                modelName = value; 
            }
        }
        private double unitCost;
        public double UnitCost
        {
            get { return unitCost; }
            set { unitCost = value; }
        }
        private string description;
        public string Description
        {
            get { return description; }
            set { description = value; }
        }
        public Product(string modelNumber,string modelName,double unitCost,string description)
        {
            ModelNumber = modelNumber;
            ModelName = modelName;
            UnitCost = unitCost;
            Description = description;
        }

        public Product() { }

    }