WPF 文本框中的必填字段验证
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Required field Validation in WPF text box
提问by kAsdh
I need a simple way to validate of text boxes (Required Field). It should check all mandatory field existence , when user press button.
我需要一种简单的方法来验证文本框（必填字段）。当用户按下按钮时，它应该检查所有必填字段是否存在。
I have tried this code :
我试过这个代码：
<Window.Resources>
<ControlTemplate x:Key="validationTemplate">
<DockPanel>
<TextBlock Foreground="Red" FontSize="25" Text="*" DockPanel.Dock="Right" />
<AdornedElementPlaceholder/>
</DockPanel>
</ControlTemplate>
</Window.Resources>
<Grid>
<Button Content="Button" HorizontalAlignment="Left" Height="26" Margin="62,213,0,0" VerticalAlignment="Top" Width="121" Click="Button_Click_1"/>
<TextBox x:Name="txtEmail1" Text="" Height="61" Margin="116,10,194,0" Validation.ErrorTemplate="{StaticResource validationTemplate}"/>
</Grid>
please anyone suggest a way to make validation in Text boxes in WPF. Thank you
请任何人建议一种在 WPF 中的文本框中进行验证的方法。谢谢
回答by mm8
You should bind the Textproperty of the TextBoxto a property of a view model and implement the IDataErrorInfointerface in the view model class.
您应该将 的Text属性绑定TextBox到视图模型的属性并IDataErrorInfo在视图模型类中实现接口。
Please refer to the following sample code.
请参考以下示例代码。
Code:
代码：
public partial class Window3 : Window
{
Window3ViewModel viewModel = new Window3ViewModel();
public Window3()
{
InitializeComponent();
DataContext = viewModel;
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
viewModel.Validate();
}
}
public class Window3ViewModel : INotifyDataErrorInfo
{
private readonly Dictionary<string, string> _validationErrors = new Dictionary<string, string>();
public void Validate()
{
bool isValid = !string.IsNullOrEmpty(_text);
bool contains = _validationErrors.ContainsKey(nameof(Text));
if (!isValid && !contains)
_validationErrors.Add(nameof(Text), "Mandatory field!");
else if (isValid && contains)
_validationErrors.Remove(nameof(Text));
if (ErrorsChanged != null)
ErrorsChanged(this, new DataErrorsChangedEventArgs(nameof(Text)));
}
public bool HasErrors => _validationErrors.Count > 0;
public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;
public IEnumerable GetErrors(string propertyName)
{
string message;
if (_validationErrors.TryGetValue(propertyName, out message))
return new List<string> { message };
return null;
}
private string _text;
public string Text
{
get { return _text; }
set
{
_text = value;
}
}
}
XAML:
XAML：
<Window x:Class="WpfApp2.Window3"
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:WpfApp2"
mc:Ignorable="d"
Title="Window3" Height="300" Width="300">
<Window.Resources>
<ControlTemplate x:Key="validationTemplate">
<DockPanel>
<TextBlock Foreground="Red" FontSize="25" Text="*" DockPanel.Dock="Right" />
<AdornedElementPlaceholder/>
</DockPanel>
</ControlTemplate>
</Window.Resources>
<Grid>
<Button Content="Button" HorizontalAlignment="Left" Height="26" Margin="62,213,0,0" VerticalAlignment="Top" Width="121" Click="Button_Click_1"/>
<TextBox x:Name="txtEmail1" Text="{Binding Text}" Height="61" Margin="116,10,194,0" Validation.ErrorTemplate="{StaticResource validationTemplate}"/>
</Grid>
</Window>
And please refer to the following blog post for more information about how data validation in WPF works.
有关 WPF 中数据验证如何工作的更多信息，请参阅以下博客文章。
Data validation in WPF:https://blog.magnusmontin.net/2013/08/26/data-validation-in-wpf/
WPF中的数据验证：https : //blog.magnusmontin.net/2013/08/26/data-validation-in-wpf/
