Question

我有一个文本框，在上面的xaml中添加了验证规则。该规则有效并且可以检测到错误，但是只有在用户将焦点放在窗口中的其他元素（例如另一个文本框）上之后。

这是定义：

<TextBox x:Name="textBoxLongitude" Grid.Row="1" Grid.Column="1" Margin="0,0,0,10" VerticalContentAlignment="Center">
        <TextBox.Text>
            <Binding Path="CustomerLongitude">
                <Binding.ValidationRules>
                    <local:IsDoubleValidationRule MaxValue ="180"/>
                </Binding.ValidationRules>
            </Binding>
        </TextBox.Text>
    </TextBox>

我尝试通过将其添加到文本框的xaml中来解决该问题：

TextChanged="textBoxTextChanged"

执行：

private void textBoxTextChanged(object sender, TextChangedEventArgs e)
{
     CommandManager.InvalidateRequerySuggested();
}

没有帮助。

我如何使验证规则能够检测到错误，以及何时修复错误，即使用户无需将焦点放在另一个控件上也可以？

Answer 1

将绑定的UpdateSourceTrigger设置为PropertyChanged，以提交并重新评估每次更改而不是LostFocus的绑定值。

Bindings that are TwoWay or OneWayToSource listen for changes in the target property and propagate them back to the source. This is known as updating the source. Usually, these updates happen whenever the target property changes. This is fine for check boxes and other simple controls, but it is usually not appropriate for text fields. Updating after every keystroke can diminish performance and it denies the user the usual opportunity to backspace and fix typing errors before committing to the new value. Therefore, the default UpdateSourceTrigger value of the Text property is LostFocus and not PropertyChanged.

这是这样做的方法：<Binding Path="CustomerLongitude" UpdateSourceTrigger="PropertyChanged">

WPF验证错误一直存在，直到控制失去重点

1 个答案: