WPF 后台触发 Validate UI‘s Element

时间:2024-09-25 12:04:20

wpf中有validateRule类, 用于界面元素的验证, 如何后台去控制validateRule呢?

1. UI层要binding写好的ValidateRule,分为Binding和MultiBinding, 如下面分别实现了Combobox的SelectedValuePropperty的Binding
     和TextBox的TextProperty的MultiBinding。其中都有ValidationRule。
       <ComboBox x:Name="cmbAgeType" Margin="3"
                      SelectionChanged="cmbAgeType_SelectionChanged"  Background="#00000000" BorderBrush="Black" Grid.Row="4" MinWidth="0" Grid.Column="2" IsTabStop="False" SelectedIndex="0" d:LayoutOverrides="GridBox" Tag="PatientAge"
                      Visibility="{Binding DataContext, ElementName=window, Converter={StaticResource KeyToVisibilityConverter}, ConverterParameter=PatientAge}">
                <ComboBox.SelectedValue>
                    <Binding Path="PatientAge" Converter="{StaticResource AgeMeasureConverter}" Mode="TwoWay"  UpdateSourceTrigger="PropertyChanged">
                        <Binding.ValidationRules>
                            <McsfPAFEContainee_ValidationRules:EmptyValidationRule ValidatesOnTargetUpdated="True" ValidationStep="ConvertedProposedValue"/>
                        </Binding.ValidationRules>
                    </Binding>
                </ComboBox.SelectedValue>
                <!--<Binding Path="PatientAge" Converter=""  UpdateSourceTrigger="PropertyChanged"/>-->
            </ComboBox>
            <TextBox x:Name="txtPatientWeight" TextWrapping="Wrap" Margin="3" MaxLength="10" TabIndex="6" BorderBrush="Black" Grid.Row="5" Grid.Column="1" Height="22" MinWidth="42" Tag="PatientWeight"
                     Visibility="{Binding DataContext, ElementName=window, Converter={StaticResource KeyToVisibilityConverter}, ConverterParameter=PatientWeight}">
                <TextBox.Text>
                    <MultiBinding  Mode="TwoWay" Converter="{StaticResource WeightConverter}"   UpdateSourceTrigger="PropertyChanged">
                        <MultiBinding.ValidationRules>
                            <McsfPAFEContainee_ValidationRules:WeightValidationRule ValidatesOnTargetUpdated="True" ValidationStep="ConvertedProposedValue"/>
                        </MultiBinding.ValidationRules>
                        <Binding Path="PatientWeight"/>
                        <Binding Path="IsChecked" ElementName="rdoKg"/>
                    </MultiBinding>
                </TextBox.Text>
                <i:Interaction.Behaviors>
                    <McsfPAFEContainee_Behaviors:NumericTextBoxBehavior MinValue="0" MaxValue="300" />
                </i:Interaction.Behaviors>
            </TextBox>
2.  后台主动触发ValidationRule的验证。 以下方法根据上面的Binding, 分别去取Binding和MultiBinding, 然后调用UpdateSource。
            private bool ValidateInput(object child, PRCfgViewModel vm, bool isUpdateSource, bool isEmergency)
        {
            BindingExpression be = null;
            MultiBindingExpression mbe = null;
            if (child is TextBox)
            {
                be = (child as TextBox).GetBindingExpression(TextBox.TextProperty);
                if (null == be)
                {
                    mbe = BindingOperations.GetMultiBindingExpression((child as TextBox), TextBox.TextProperty);
                }
            }
            else if (child is DatePicker)
            {
                be = (child as DatePicker).GetBindingExpression(DatePicker.TextProperty);
                if (null == be)
                {
                    mbe = BindingOperations.GetMultiBindingExpression((child as DatePicker), DatePicker.TextProperty);
                }
            }
            else if (child is ComboBox)
            {
                be = (child as ComboBox).GetBindingExpression(ComboBox.SelectedValueProperty);
                if (null == be)
                {
                    mbe = BindingOperations.GetMultiBindingExpression((child as ComboBox), ComboBox.SelectedValueProperty);
                }
            }
            if (null == be && null == mbe)
            {
                return false;
            }
            ValidationRule vr = null;
            if (null != be && be.ParentBinding.ValidationRules.Count > 0)
            {
                vr = be.ParentBinding.ValidationRules[0];
            }
            else if (null != mbe && mbe.ParentMultiBinding.ValidationRules.Count > 0)
            {
                vr = mbe.ParentMultiBinding.ValidationRules[0];
            }
            else
            {
                return false;
            }
            string bindingPath = "";
            if (null != be)
            {
                bindingPath = be.ParentBinding.Path.Path;
            }
            else if (null != mbe)
            {
                Binding bd = mbe.ParentMultiBinding.Bindings[0] as Binding;
                bindingPath = bd.Path.Path;
            }
            bindingPath = bindingPath.Replace(".", "_");
            if (vm.Setting.CfgInfo[bindingPath] != null)
            {
                (vr as BaseValidationRule).IsActive = !isEmergency;
                if ((vr as BaseValidationRule).IsActive)
                {
                    (vr as BaseValidationRule).IsAllowEmpty = !(vm.Setting.CfgInfo[bindingPath].IsKeyword);
                }
                else
                {
                    if (isUpdateSource)
                    {
                        if (null != be)
                        {
                            be.UpdateSource();
                        }
                        else if (null != mbe)
                        {
                            mbe.UpdateSource();
                        }
                    }
                    return true;
                }
            }
            else
            {
                (vr as BaseValidationRule).IsAllowEmpty = true;
            }
            if (isUpdateSource)
            {
                if (null != be)
                {
                    be.UpdateSource();
                }
                else if (null != mbe)
                {
                    mbe.UpdateSource();
                }
            }
            return true;
        }