求WPF 录入为空验证简单代码

[山之魂2]

在做一个WPF项目，录入项还没有加验证提示。
求WPF 录入为空显示 红色 * 号的简单代码

[ylly11111]

<Window x:Class="ErrorTest.MainWindow"
        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:local="clr-namespace:ErrorTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <TextBox HorizontalAlignment="Left"  
                 Height="50"   VerticalAlignment="Top" Width="237">
            <TextBox.Text>
                <Binding Path="FName"  NotifyOnValidationError="True"   
                    UpdateSourceTrigger="PropertyChanged">
                    <Binding.ValidationRules>
                        <local:ValidClass></local:ValidClass>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

    </Grid>
</Window>

添加一个验证文件

  public class ValidClass : ValidationRule
    {
        public override ValidationResult Validate(object value, CultureInfo cultureInfo)
        {
            var a = value.ToString();
            if (string.IsNullOrWhiteSpace(a))
            {
                return new ValidationResult(false, "不可为空");
            }
            else
            {
                return new ValidationResult(true, null);
            }
        }
    }

添加一个ViewModel

    public class VM : INotifyPropertyChanged
    {
 
        private string _FName;

        public string FName
        {
            get { return _FName; }
            set { _FName = value; RaisePropertyChanged("FName"); }
        }
 
        private void RaisePropertyChanged(string name)
        {
            if (PropertyChanged != null)
                PropertyChanged(this,new PropertyChangedEventArgs (name));
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }

[山之魂2]

引用 2 楼 ylly11111 的回复:

<Window x:Class="ErrorTest.MainWindow"
        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:local="clr-namespace:ErrorTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <TextBox HorizontalAlignment="Left"  
                 Height="50"   VerticalAlignment="Top" Width="237">
            <TextBox.Text>
                <Binding Path="FName"  NotifyOnValidationError="True"   
                    UpdateSourceTrigger="PropertyChanged">
                    <Binding.ValidationRules>
                        <local:ValidClass></local:ValidClass>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

    </Grid>
</Window>

添加一个验证文件

  public class ValidClass : ValidationRule
    {
        public override ValidationResult Validate(object value, CultureInfo cultureInfo)
        {
            var a = value.ToString();
            if (string.IsNullOrWhiteSpace(a))
            {
                return new ValidationResult(false, "不可为空");
            }
            else
            {
                return new ValidationResult(true, null);
            }
        }
    }

添加一个ViewModel

    public class VM : INotifyPropertyChanged
    {
 
        private string _FName;

        public string FName
        {
            get { return _FName; }
            set { _FName = value; RaisePropertyChanged("FName"); }
        }
 
        private void RaisePropertyChanged(string name)
        {
            if (PropertyChanged != null)
                PropertyChanged(this,new PropertyChangedEventArgs (name));
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }

谢谢，我昨天下午查资料写出来了，跟你这个基本上一样，非常感谢。

[山之魂2]

TextBox的按二楼的方法，加一个样式做出来了。 现在还缺Combobox 为空提示的验证，如果有人有可用代码的话给一下，可以另开一贴或者加200分给他，先谢谢了

[郑州高新区WPF小王子]

验证错误提示默认是红色的边框 自定义的话修改它的ErrorTemplate 模板