• WPF 使用MultiBinding ,TwoWay ,ValidationRule ,需要注意的事项


    当wpf使用multibinding时, 其内部的validaterule的value 是其多个Binding的值, 要根据情况去验证, 还有就是在做IMultiConverter的ConvertBack时注意TargetType

    如: 以下是一个Textbox通过MultiBinding绑定到后台 的字段, 以及前台的一个radiobutton, 该textbox有个validaterule。 



     <TextBox x:Name="txtPatientWeight" TextWrapping="Wrap" Margin="3" MaxLength="5" 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}">
                    <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>
                    <i:Interaction.Behaviors>
                        <McsfPAFEContainee_Behaviors:NumericTextBoxBehavior MinValue="0" MaxValue="300" />
                    </i:Interaction.Behaviors>
                </TextBox>
    ////////////////////////
     <RadioButton x:Name="rdoKg" Content="kg" GroupName="WeightMeasure" d:LayoutOverrides="GridBox" MinWidth="34" Margin="5,0,0,0" Tag="PatientWeight" HorizontalAlignment="Center">
                        <RadioButton.IsChecked>
                            <Binding Path="DataContext" Mode="TwoWay" ElementName="window" Converter="{StaticResource DefaultUnitConverter}" ConverterParameter="kg"  UpdateSourceTrigger="PropertyChanged"></Binding>
                        </RadioButton.IsChecked>
                    </RadioButton>

      private string patientWeight = "";//(0010,1030) Patient Weight PatientWeight DS unit kg

            public string PatientWeight
            {
                get { return patientWeight; }
                set
                {
                    if (value == patientWeight)
                    {
                        return;
                    }

                    patientWeight = value;
                    OnPropertyChanged("PatientWeight");
                }
            }
      


     public class WeightConverter : IMultiValueConverter
        {
            public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
            {
                if (null == values || 2 != values.Length )
                {
                    return "";
                }

                string unit = "";
                string temp = values[0].ToString();

                if (String.IsNullOrEmpty(temp))
                {
                    return "";
                }

                if (0 <= temp.IndexOf("lb"))
                {
                    unit = "lb";
                }
                else if (0 <= temp.IndexOf("kg"))
                {
                    unit = "kg";
                }
                else
                {
                    return "";
                }

                string number = "";
                number = temp.Substring(0, temp.IndexOf(unit));

                //KG
                if ((bool)values[1])
                {
                    measurementUnit = "kg";
                }
                else //LB
                {
                    measurementUnit = "lb";
                }

                return ConvertToTargetValue(number, unit, measurementUnit);
            }

            private string measurementUnit = "";
          
            public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
            {
                string temp = value.ToString();

                if (String.IsNullOrEmpty(temp))
                {
                    return new object[]{DependencyProperty.UnsetValue, DependencyProperty.UnsetValue};
                }

                if (String.IsNullOrEmpty(measurementUnit))
                {
                    measurementUnit = (PAFEContainee.MainDataContext as MainViewModel).PRCfgVM.IsDefaultKilogram ? "kg" : "lb";
                }

                object[] list = new object[2];
                list[0] = value.ToString() + measurementUnit;
                list[1] = measurementUnit.Equals("kg") ? "true" : "false";

                return list;
            }

            private string ConvertToTargetValue(string before, string beforeUnit, string afterUnit)
            {
                string result = "";

                if (beforeUnit.Equals(afterUnit))
                {
                    return before;
                }

                switch (afterUnit)
                {
                    case "lb":
                        result = ConvertKgToPound(before).ToString();
                        break;
                    case "kg":
                        result = ConvertPoundToKg(before).ToString();
                        break;
                    default:
                        break;
                }

                return result;
            }

            private double ConvertPoundToKg(string pound)
            {
                double kg = 0.4536 * double.Parse(pound);

                return kg;
            }

            private double ConvertKgToPound(string kg)
            {
                double pound = 2.20 * double.Parse(kg);

                return pound;
            }

        }


     public override ValidationResult DoValidate(object value, CultureInfo cultureInfo)
            {
                try
                {

                    //string field = value.ToString().Trim();
                    string field = (value as object[])[0].ToString();
                    string pattern = @"^([1-9]|[1-9][0-9]|[1-5][0-9][0-9]|600)((kg)|(lb))$";

                    Regex reg = new Regex(pattern, RegexOptions.IgnoreCase);

                    if (field.Length <= 0 || false == reg.IsMatch(field))
                    {
                        return new ValidationResult(false, "Please input a number, for example '60'");
                    }
                    else
                    {
                        return ValidationResult.ValidResult;
                    }
                }
                catch
                {
                    return new ValidationResult(false, "Patient weight convert failed.");
                }

            }
    https://muzizongheng.blog.csdn.net/
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  • 原文地址:https://www.cnblogs.com/muzizongheng/p/3166597.html
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