WPF简单验证问题-设置自定义ErrorContent

本文关键字:设置 自定义 ErrorContent 问题 简单 验证 WPF | 更新日期: 2023-09-27 17:57:53

如果我有以下TextBox:

<TextBox Height="30" Width="300" Margin="10" Text="{Binding IntProperty, 
       NotifyOnValidationError=True}" Validation.Error="ContentPresenter_Error">
</TextBox>

这个在代码后面:

private void ContentPresenter_Error(object sender, ValidationErrorEventArgs e) {
   MessageBox.Show(e.Error.ErrorContent.ToString());
}

如果我在文本框中输入字母"x",则弹出的消息为

无法转换值"x"

是否有自定义此消息的方法?

WPF简单验证问题-设置自定义ErrorContent

我不喜欢回答自己的问题,但似乎唯一的方法是实现ValidationRule,如下所示(其中可能有一些错误):

public class BasicIntegerValidator : ValidationRule {       
    public string PropertyNameToDisplay { get; set; }
    public bool Nullable { get; set; }
    public bool AllowNegative { get; set; }
    string PropertyNameHelper { get { return PropertyNameToDisplay == null ? string.Empty : " for " + PropertyNameToDisplay; } }
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo) {
        string textEntered = (string)value;
        int intOutput;
        double junkd;
        if (String.IsNullOrEmpty(textEntered))
            return Nullable ? new ValidationResult(true, null) : new ValidationResult(false, getMsgDisplay("Please enter a value"));
        if (!Int32.TryParse(textEntered, out intOutput))
            if (Double.TryParse(textEntered, out junkd))
                return new ValidationResult(false, getMsgDisplay("Please enter a whole number (no decimals)"));
            else
                return new ValidationResult(false, getMsgDisplay("Please enter a whole number"));
        else if (intOutput < 0 && !AllowNegative)
            return new ValidationResult(false, getNegativeNumberError());
        return new ValidationResult(true, null);
    }
    private string getNegativeNumberError() {
        return PropertyNameToDisplay == null ? "This property must be a positive, whole number" : PropertyNameToDisplay + " must be a positive, whole number";
    }
    private string getMsgDisplay(string messageBase) {
        return String.Format("{0}{1}", messageBase, PropertyNameHelper);
    }
}

您可以使用ValidationRules。

例如,在我的案例中,当用户在十进制datagridtext列中输入无效值时,我可以用覆盖它,而不是默认消息"value cannot be converted"

<DataGridTextColumn x:Name="Column5" Header="{x:Static p:Resources.Waste_perc}" Width="auto">
    <DataGridTextColumn.Binding>
        <Binding Path="Waste" ValidatesOnDataErrors="True" UpdateSourceTrigger="LostFocus">
            <Binding.ValidationRules>
                <myLib:DecimalRule />
            </Binding.ValidationRules>
        </Binding>
    </DataGridTextColumn.Binding>
</DataGridTextColumn>

这是十进制规则的代码:

public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
    decimal convertedDecimal;
    if (!decimal.TryParse((string)value, out convertedDecimal))
    {
        return new ValidationResult(false, "My Custom Message"));
    }
    else
    {
        return new ValidationResult(true, null);
    }
}