A common booltoxxx conversion class in WPF

InWPFProgramIn data binding, it is often controlled by a Boolean value.UIControl status, such as whether to be visible or maximize. HoweverUIThe status attribute types of the control are usually not boolean. For exampleUielement. VisibilityIsVisibilityEnumeration,Window. windowstateIsWindowstateEnumeration. I used to write a lotValueconverterFor exampleBooltovisibilityconverterLA,BooltowindowstateconverterIt's very troublesome. Describes a commonBooltoxxxConversion class, which usesBindingObjectConverterparameterAndFallbackvalueTo convert the Boolean Type and any value.

ConverterparameterWhen binding dataUIUploadValueconverterFor example, to convert a string to an integer through data binding, you can useConverterparameterIn decimal or hexadecimal format. WhileFallbackvalueWhen data binding cannot provide a meaningful value (by returningDependencyproperty. unsetvalueThis value), the data binding engine will useFallbackvalueThe value specified in.

First lookBooltovalueconverterOfSource code:

Public Class Booltovalueconverter:Ivalueconverter { # RegionIvalueconverter members   Public ObjectConvert (ObjectValue,TypeTargettype,ObjectParameter,CultureinfoCulture) { If((Bool) Value) ReturnParameter; Else Return Dependencyproperty. Unsetvalue; }   Public ObjectConvertback (ObjectValue,TypeTargettype,ObjectParameter,CultureinfoCulture) { Return Object. Equals (value, parameter ); }   # Endregion }

 

convert function, by judging the bound Boolean value, if it is true ( true ), use binding converterparameter attribute saved value. If the value is false ( false ), dependencyproperty is returned. unsetvalue tells the Data Binding engine to use Binding fallbackvalue of the object. convertback is used to determine UI value of the property corresponding to the object (for example, uielement. visibility ) Is it consistent with the preset value (for example, visibility. visible ) is the same, and the corresponding value is returned. You can also use the Code below to learn booltovalueconverter usage - note the highlighted yellow part:

Booltovaluetestwindow. XAML: <WindowX:Class= "Manualtestproject. wpflibtest. booltovaluetestwindow" Xmlns= "Http://schemas.microsoft.com/winfx/2006/xaml/presentation" Xmlns:X= "Http://schemas.microsoft.com/winfx/2006/xaml" Xmlns:Converter= "CLR-namespace: wpflib. converters; Assembly = wpflib" Title= "Booltovaluetestwindow"Height= "300"Width= "300"X:Name= "Layoutroot"> <Window. Resources> <Converter:BooltovalueconverterX:Key= "Booltovalueconverter"/> </Window. Resources> <Stackpanel> <CheckboxIschecked= "{BindingElementname= Layoutroot,Path= Boolvalue }" Content= "Check box"/> <ButtonContent= "True" Visibility = "{ Binding Elementname = Layoutroot, Path = Boolvalue, Converter = { Staticresource Booltovalueconverter }, Converterparameter = Visible, Fallbackvalue = Collapsed }" X:Name= "Truebutton"Click= "Truebutton_click"/> <ButtonContent= "False" Visibility = "{ Binding Elementname = Layoutroot, Path = Boolvalue, Converter = { Staticresource Booltovalueconverter }, Converterparameter = Collapsed, Fallbackvalue = Visible }" X:Name= "Falsebutton"Click= "Falsebutton_click"/> </Stackpanel> </Window>   Booltovaluetestwindow. XAML. CS: Public Partial Class Booltovaluetestwindow:Window { Public BoolBoolvalue { Get{Return(Bool) Getvalue (boolvalueproperty );} Set{Setvalue (boolvalueproperty,Value);} }   Public Static Readonly DependencypropertyBoolvalueproperty = Dependencyproperty. Register ("Boolvalue", Typeof(Bool), Typeof(Booltovaluetestwindow), New Uipropertymetadata(False));   PublicBooltovaluetestwindow () { Initializecomponent (); }   Private VoidTruebutton_click (ObjectSender,RoutedeventargsE) { Boolvalue =False; }   Private VoidFalsebutton_click (ObjectSender,RoutedeventargsE) { Boolvalue =True; } }