WPF简单的验证问题 - 设置自定义ErrorContent [英] WPF Simple Validation Question - setting custom ErrorContent

问题描述

如果我有下面的文本框：

If I have the following TextBox:

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

这在代码隐藏：

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

如果我输入在文本框中输入字母X的消息，弹出是

If I enter the letter "x" in the text box, the message that pops up is

值'X'不能转换

有没有一种方法来定制这个消息？

Is there a way to customize this message?

推荐答案

我不喜欢回答我的问题，但它似乎要做到这一点的唯一方法是实现一个有效性规则，像什么是下面（有可能是它的一些错误）：

I dislike answering my own question, but it appears the only way to do this is to implement a ValidationRule, like what's below (there may be some bugs in it):

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);
    }
}

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