Trigger.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Trigger.cs / 1305600 / Trigger.cs
                        
                        
                            using MS.Utility; 
using System.IO;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Windows.Markup; 

using System; 
using System.Diagnostics; 
using System.Globalization;
using MS.Internal; 

namespace System.Windows
{
    ///  
    ///     A single Style property conditional dependency driver
    ///  
    [ContentProperty("Setters")] 
    [XamlSetTypeConverterAttribute("ReceiveTypeConverter")]
    public class Trigger : TriggerBase, IAddChild, ISupportInitialize 
    {
        /// 
        ///     DependencyProperty of the conditional
        ///  
        [Ambient]
        [Localizability(LocalizationCategory.None, Modifiability = Modifiability.Unmodifiable, Readability = Readability.Unreadable)] // Not localizable by-default 
        public DependencyProperty Property 
        {
            get 
            {
                // Verify Context Access
                VerifyAccess();
 
                return _property;
            } 
            set 
            {
                // Verify Context Access 
                VerifyAccess();

                if (IsSealed)
                { 
                    throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "Trigger"));
                } 
 
                _property = value;
            } 
        }

        /// 
        ///     Value of the condition (equality check) 
        /// 
        [DependsOn("Property")] 
        [DependsOn("SourceName")] 
        [Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // Not localizable by-default
        [TypeConverter(typeof(SetterTriggerConditionValueConverter))] 
        public object Value
        {
            get
            { 
                // Verify Context Access
                VerifyAccess(); 
 
                return _value;
            } 
            set
            {
                // Verify Context Access
                VerifyAccess(); 

                if (IsSealed) 
                { 
                    throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "Trigger"));
                } 

                if (value is NullExtension)
                {
                    value = null; 
                }
 
                if (value is MarkupExtension) 
                {
                    throw new ArgumentException(SR.Get(SRID.ConditionValueOfMarkupExtensionNotSupported, 
                                                       value.GetType().Name));
                }

                if (value is Expression) 
                {
                    throw new ArgumentException(SR.Get(SRID.ConditionValueOfExpressionNotSupported)); 
                } 

                _value = value; 
            }
        }

        ///  
        /// The x:Name of the object whose property shall
        /// trigger the associated setters to be applied. 
        /// If null, then this is the object being Styled 
        /// and not anything under its Template Tree.
        ///  
        [DefaultValue(null)]
        [Ambient]
        public string SourceName
        { 
            get
            { 
                // Verify Context Access 
                VerifyAccess();
 
                return _sourceName;
            }
            set
            { 
                // Verify Context Access
                VerifyAccess(); 
 
                if( IsSealed )
                { 
                    throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "Trigger"));
                }

                _sourceName = value; 
            }
        } 
 
        /// 
        /// Collection of Setter objects, which describes what to apply 
        /// when this trigger is active.
        /// 
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public SetterBaseCollection Setters 
        {
            get 
            { 
                // Verify Context Access
                VerifyAccess(); 

                if( _setters == null )
                {
                    _setters = new SetterBaseCollection(); 
                }
                return _setters; 
            } 
        }
 
        ///
        /// This method is called to Add a Setter object as a child of the Style.
        ///
        /// 
        /// The object to add as a child; it must be a Setter or subclass.
        /// 
        void IAddChild.AddChild (Object value) 
        {
            // Verify Context Access 
            VerifyAccess();

            Setters.Add(Trigger.CheckChildIsSetter(value));
        } 

        /// 
        /// This method is called by the parser when text appears under the tag in markup. 
        /// As default Styles do not support text, calling this method has no effect.
        /// 
        ///
        /// Text to add as a child.
        ///
        void IAddChild.AddText (string text) 
        {
            // Verify Context Access 
            VerifyAccess(); 

            XamlSerializerUtil.ThrowIfNonWhiteSpaceInAddText(text, this); 
        }

        // Shared by PropertyTrigger, MultiPropertyTrigger, DataTrigger, MultiDataTrigger
        internal static Setter CheckChildIsSetter( object o ) 
        {
            if (o == null) 
            { 
                throw new ArgumentNullException("o");
            } 

            Setter setter = o as Setter;

            if (setter == null) 
            {
                throw new ArgumentException(SR.Get(SRID.UnexpectedParameterType, o.GetType(), typeof(Setter)), "o"); 
            } 

            return setter; 
        }

        internal sealed override void Seal()
        { 
            if (IsSealed)
            { 
                return; 
            }
 
            if (_property != null)
            {
                // Ensure valid condition
                if (!_property.IsValidValue(_value)) 
                {
                    throw new InvalidOperationException(SR.Get(SRID.InvalidPropertyValue, _value, _property.Name )); 
                } 
            }
 
            // Freeze the condition for the trigger
            StyleHelper.SealIfSealable(_value);

            // Process the _setters collection: Copy values into PropertyValueList and seal the Setter objects. 
            ProcessSettersCollection(_setters);
 
            // Build conditions array from collection 
            TriggerConditions = new TriggerCondition[] {
                new TriggerCondition( 
                    _property,
                    LogicalOp.Equals,
                    _value,
                    (_sourceName != null) ? _sourceName : StyleHelper.SelfName) }; 

            // Set Condition for all property triggers 
            for (int i = 0; i < PropertyValues.Count; i++) 
            {
                PropertyValue propertyValue = PropertyValues[i]; 
                propertyValue.Conditions = TriggerConditions;
                // Put back modified struct
                PropertyValues[i] = propertyValue;
            } 

            base.Seal(); 
        } 

        // evaluate the current state of the trigger 
        internal override bool GetCurrentState(DependencyObject container, UncommonField dataField)
        {
            Debug.Assert( TriggerConditions != null && TriggerConditions.Length == 1,
                "This method assumes there is exactly one TriggerCondition." ); 

            Debug.Assert( TriggerConditions[0].SourceChildIndex == 0, 
                "This method was created to handle properties on the containing object, more work is needed to handle templated children too." ); 

            return TriggerConditions[0].Match(container.GetValue(TriggerConditions[0].Property)); 
        }

        #region ISupportInitialize Members
 
        void ISupportInitialize.BeginInit()
        { 
        } 

        void ISupportInitialize.EndInit() 
        {
            // Resolve all properties here
            if (_unresolvedProperty != null)
            { 
                try
                { 
                    Property = DependencyPropertyConverter.ResolveProperty(_serviceProvider, 
                        SourceName, _unresolvedProperty);
                } 
                finally
                {
                    _unresolvedProperty = null;
                } 
            }
            if (_unresolvedValue != null) 
            { 
                try
                { 
                    Value = SetterTriggerConditionValueConverter.ResolveValue(_serviceProvider,
                        Property, _cultureInfoForTypeConverter, _unresolvedValue);
                }
                finally 
                {
                    _unresolvedValue = null; 
                } 
            }
            _serviceProvider = null; 
            _cultureInfoForTypeConverter = null;
        }

        #endregion 

        public static void ReceiveTypeConverter(object targetObject, XamlSetTypeConverterEventArgs eventArgs) 
        { 
            Trigger trigger = targetObject as Trigger;
            if (trigger == null) 
            {
                throw new ArgumentNullException("targetObject");
            }
            if (eventArgs == null) 
            {
                throw new ArgumentNullException("eventArgs"); 
            } 

            if (eventArgs.Member.Name == "Property") 
            {
                trigger._unresolvedProperty = eventArgs.Value;
                trigger._serviceProvider = eventArgs.ServiceProvider;
                trigger._cultureInfoForTypeConverter = eventArgs.CultureInfo; 

                eventArgs.Handled = true; 
            } 
            else if (eventArgs.Member.Name == "Value")
            { 
                trigger._unresolvedValue = eventArgs.Value;
                trigger._serviceProvider = eventArgs.ServiceProvider;
                trigger._cultureInfoForTypeConverter = eventArgs.CultureInfo;
 
                eventArgs.Handled = true;
            } 
        } 

        private DependencyProperty _property; 
        private object _value = DependencyProperty.UnsetValue;
        private string _sourceName = null;
        private SetterBaseCollection _setters = null;
        private object _unresolvedProperty = null; 
        private object _unresolvedValue = null;
        private ITypeDescriptorContext _serviceProvider = null; 
        private CultureInfo _cultureInfoForTypeConverter = null; 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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Trigger.cs source code in C# .NET

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