WPF 使用MultiBinding ，TwoWay ，ValidationRule ，需要注意的事项 · WPF编程之路

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。 <TextBoxx: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="{BindingDataContext,ElementName=window,Converter={StaticResourceKeyToVisibilityConverter},ConverterParameter=PatientWeight}"> <MultiBinding Mode="TwoWay"Converter="{StaticResourceWeightConverter}" UpdateSourceTrigger="PropertyChanged"> <MultiBinding.ValidationRules> <McsfPAFEContainee_ValidationRules:WeightValidationRuleValidatesOnTargetUpdated="True"ValidationStep="ConvertedProposedValue"/> </MultiBinding.ValidationRules> <BindingPath="PatientWeight"/> <BindingPath="IsChecked"ElementName="rdoKg"/> </MultiBinding> <i:Interaction.Behaviors> <McsfPAFEContainee_Behaviors:NumericTextBoxBehaviorMinValue="0"MaxValue="300" /> </i:Interaction.Behaviors> </TextBox> //////////////////////// <RadioButtonx:Name="rdoKg"Content="kg"GroupName="WeightMeasure"d:LayoutOverrides="GridBox"MinWidth="34"Margin="5,0,0,0"Tag="PatientWeight"HorizontalAlignment="Center"> <RadioButton.IsChecked> <BindingPath="DataContext"Mode="TwoWay"ElementName="window"Converter="{StaticResourceDefaultUnitConverter}"ConverterParameter="kg" UpdateSourceTrigger="PropertyChanged"></Binding> </RadioButton.IsChecked> </RadioButton> [//////////////]() privatestringpatientWeight="";//(0010,1030) Patient Weight PatientWeight DS unit kg publicstringPatientWeight { get{returnpatientWeight; } set { if(value==patientWeight) { return; } patientWeight=value; OnPropertyChanged("PatientWeight"); } } [//////////converter]() publicclassWeightConverter:IMultiValueConverter { publicobjectConvert(object[] values,TypetargetType,objectparameter,CultureInfoculture) { if(null== values || 2 != values.Length ) { return""; } stringunit =""; stringtemp = values[0].ToString(); if(String.IsNullOrEmpty(temp)) { return""; } if(0 <= temp.IndexOf("lb")) { unit ="lb"; } elseif(0 <= temp.IndexOf("kg")) { unit ="kg"; } else { return""; } stringnumber =""; number = temp.Substring(0, temp.IndexOf(unit)); //KG if((bool)values[1]) { measurementUnit ="kg"; } else//LB { measurementUnit ="lb"; } returnConvertToTargetValue(number, unit, measurementUnit); } privatestringmeasurementUnit =""; publicobject[] ConvertBack(objectvalue,Type[] targetTypes,objectparameter,CultureInfoculture) { stringtemp = value.ToString(); if(String.IsNullOrEmpty(temp)) { returnnewobject[]{DependencyProperty.UnsetValue,DependencyProperty.UnsetValue}; } if(String.IsNullOrEmpty(measurementUnit)) { measurementUnit = (PAFEContainee.MainDataContextasMainViewModel).PRCfgVM.IsDefaultKilogram ?"kg":"lb"; } object[] list =newobject[2]; list[0] = value.ToString() + measurementUnit; list[1] = measurementUnit.Equals("kg") ?"true":"false"; returnlist; } privatestringConvertToTargetValue(stringbefore,stringbeforeUnit,stringafterUnit) { stringresult =""; if(beforeUnit.Equals(afterUnit)) { returnbefore; } switch(afterUnit) { case"lb": result = ConvertKgToPound(before).ToString(); break; case"kg": result = ConvertPoundToKg(before).ToString(); break; default: break; } returnresult; } privatedoubleConvertPoundToKg(stringpound) { doublekg = 0.4536 *double.Parse(pound); returnkg; } privatedoubleConvertKgToPound(stringkg) { doublepound = 2.20 *double.Parse(kg); returnpound; } } [///////ValidationRule]() publicoverrideValidationResultDoValidate(objectvalue,CultureInfocultureInfo) { try { //string field = value.ToString().Trim(); stringfield= (valueasobject[])[0].ToString(); stringpattern=@"^([1-9]|[1-9][0-9]|[1-5][0-9][0-9]|600)((kg)|(lb))$"; Regexreg=newRegex(pattern,RegexOptions.IgnoreCase); if(field.Length<= 0 ||false==reg.IsMatch(field)) { returnnewValidationResult(false,"Please input a number, for example '60'"); } else { returnValidationResult.ValidResult; } } catch { returnnewValidationResult(false,"Patient weight convert failed."); } }