Question

我正在尝试在WPF中使用文本框进行验证。问题是当没有数据输入文本框时会导致验证错误，没有显示validataion错误。有人可以给我一些帮助吗？先感谢您。这是我的代码

public class User
    {
        private string _name;

        public string myName
        {
            get { return _name; }
            set
            {
                _name = value;
                if (String.IsNullOrEmpty(value))
                {
                    throw new ApplicationException("User name is mandatory.");
                }
            }
        }
    }

<TextBox Height="23"
                 HorizontalAlignment="Right"
                 Margin="0,0,194,250" Name="textBox1"
                 VerticalAlignment="Bottom"
                 Width="120" >
                <TextBox.Text>
                    <Binding Path="myName" >
                        <Binding.ValidationRules>
                            <ExceptionValidationRule />
                        </Binding.ValidationRules>
                    </Binding>
                </TextBox.Text>
        </TextBox>

编辑：我确实遇到了绑定问题。我修复了我的代码，这里是：我开始创建用户和错误模板：

<local:User x:Key="myDataSource" myName="Enter Name" />

        <ControlTemplate x:Key="validationTemplate">
            <DockPanel>
                <TextBlock Foreground="Red" FontSize="20">!!!</TextBlock>
                <AdornedElementPlaceholder/>
            </DockPanel>
        </ControlTemplate>

如果存在验证错误，我会禁用保存按钮

<Button Content="Write Kml"
                Height="23"
                HorizontalAlignment="Right"
                Margin="0,0,12,41"
                Name="writeKml"
                VerticalAlignment="Bottom"
                Width="75" Click="button2_Click" >
            <Button.Style>
                <Style TargetType="{x:Type Button}">
                    <Setter Property="IsEnabled" Value="false" />
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding ElementName=textBox1, Path=(Validation.HasError)}" Value="false">
                            <Setter Property="IsEnabled" Value="true" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Button.Style>
        </Button>

然后我修复了textBox以允许正确的验证

<TextBox Height="23"
                 HorizontalAlignment="Right"
                 Margin="0,0,194,250"
                 Name="textBox1"
                 VerticalAlignment="Bottom"
                 Validation.ErrorTemplate="{StaticResource validationTemplate}"
                 Width="120" >
                <TextBox.Text>
                    <Binding
                        Source="{StaticResource myDataSource}"
                        Path="myName"
                        UpdateSourceTrigger="PropertyChanged"
                        ValidatesOnExceptions="True"
                        ValidatesOnDataErrors="True" >
                        <Binding.ValidationRules>
                            <local:CheckName />
                        </Binding.ValidationRules>
                    </Binding>
                </TextBox.Text>
        </TextBox>

这是背后的代码

public class User
    {
        private string _name;

        public string myName
        {
            get { return _name; }
            set { _name = value; }
        }
    }

    public class CheckName : ValidationRule
    {
        public override ValidationResult Validate(object value, CultureInfo cultureInfo)
        {
            if (value == null || object.Equals(value, string.Empty))
            {
                return new ValidationResult(false, "Please enter user name");
            }

            if (value.ToString() == "Enter Name")
            {
                return new ValidationResult(false, "Please enter user name");
            }

            return new ValidationResult(true, null);
        }
    }

最后我将代码添加到窗口加载的例程中以强制验证

private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            textBox1.GetBindingExpression(TextBox.TextProperty).UpdateSource();
        }

我希望这有助于任何试图在WPF中验证文本框的人。

Answer 1

您的User类需要实现INotifyPropertyChanged才能在WPF中支持数据绑定。您可能需要对WPF和数据绑定进行一些阅读，因为它是构建WPF（或Silverlight）应用程序所需的基础知识。

情侣链接让您入门：

Data Binding Overview

INotifyPropertyChanged Interface

TextBox验证问题

1 个答案: