Trigger.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Trigger.cs / 1 / Trigger.cs

                            using MS.Utility; 
using System.IO;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Windows.Markup; 

using System; 
using System.Diagnostics; 

namespace System.Windows 
{
    /// 
    ///     A single Style property conditional dependency driver
    ///  
    [ContentProperty("Setters")]
    public class Trigger : TriggerBase, IAddChild 
    { 
        /// 
        ///     DependencyProperty of the conditional 
        /// 
        [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 
        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 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)] 
        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)); 
        }
 
        private DependencyProperty _property;
        private object _value = DependencyProperty.UnsetValue;
        private string _sourceName = null;
        private SetterBaseCollection _setters = null; 
    }
} 
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
                        

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