ControlCollection.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / ControlCollection.cs / 1 / ControlCollection.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI { 
    using System.Runtime.InteropServices; 

    using System; 
    using System.Collections;
    using System.Security.Permissions;

 
    /// 
    ///     
    ///       The  class provides a 
    ///       collection container that enables a control to maintain a
    ///       list of its child controls. 
    ///
    ///       For performance reasons, this is internally strongly typed. Most implementation is copied from
    ///       ArrayList.cs
    ///     
    /// 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    public class ControlCollection : ICollection {
        private Control _owner; 
        private Control[] _controls;
        private int _size;
        private int _version;
        private string _readOnlyErrorMsg = null; 

        private int _defaultCapacity = 5; 
        private int _growthFactor = 4; 

 
        /// 
        ///    [To be supplied.]
        /// 
        public ControlCollection(Control owner) { 
            if (owner == null) {
                throw new ArgumentNullException("owner"); 
            } 
            _owner = owner;
        } 

        internal ControlCollection(Control owner, int defaultCapacity, int growthFactor) {
            if (owner == null) {
                throw new ArgumentNullException("owner"); 
            }
            _owner = owner; 
            _defaultCapacity = defaultCapacity; 
            _growthFactor = growthFactor;
        } 

        /*
         * Adds a child control to this control.
         */ 

        ///  
        /// Adds the specified  object 
        ///    to the collection. The new control is logically added to the end of an ordinal
        ///    index array. 
        /// 
        public virtual void Add(Control child) {
            // Note: duplication of code with AddAt is deliberate for performance reasons. This is the more common form of the call.
 
            // Check arguments
            if (child == null) 
                throw new ArgumentNullException("child"); 

            if (_readOnlyErrorMsg != null) { 
                throw new HttpException(SR.GetString(_readOnlyErrorMsg ));
            }

            // Make sure we have room 
            if (_controls == null) {
                _controls = new Control[_defaultCapacity]; 
            } 
            else if (_size >= _controls.Length) {
                Control[] newArray = new Control[_controls.Length * _growthFactor ]; 
                Array.Copy(_controls, newArray, _controls.Length);
                _controls = newArray;
            }
 
            // Add the control
            int index = _size; 
            _controls[index] = child; 
            _size++;
            _version++; 

            // Notify Owner
            _owner.AddedControl(child, index);
        } 

        /* 
         * Adds a child control to this control at a certain index 
         */
 
        /// 
        /// Adds the specified  object to the collection. The new control is added
        ///    to the array at the specified index location.
        ///  
        public virtual void AddAt(int index, Control child) {
 
            // For compatability, we must support this. 
            if (index == -1) {
                Add(child); 
                return;
            }

            // Check Arguments 
            if (child == null) {
                throw new ArgumentNullException("child"); 
            } 
            if (index < 0 || index > _size) {
                throw new ArgumentOutOfRangeException("index"); 
            }

            if (_readOnlyErrorMsg != null) {
                throw new HttpException(SR.GetString(_readOnlyErrorMsg )); 
            }
 
            // Make sure we have room 
            if (_controls == null) {
                _controls = new Control[_defaultCapacity]; 
            }
            else if (_size >= _controls.Length) {
                //expand
                Control[] newArray = new Control[_controls.Length * _growthFactor ]; 
                //copy precedents
                Array.Copy(_controls, newArray, index); 
                //insert 
                newArray[index] = child;
                //copy antecedents 
                Array.Copy(_controls, index, newArray, index+1, _size - index);
                _controls = newArray;
            }
            // Insert the control 
            else if (index < _size) {
                Array.Copy(_controls, index, _controls, index + 1, _size - index); 
            } 
            _controls[index] = child;
            _size++; 
            _version++;

            _owner.AddedControl(child, index);
        } 

 
        ///  
        ///    
        ///       Removes all controls in the collection. 
        ///    
        /// 
        public virtual void Clear() {
            if (_controls != null) { 
                // ASURT 123965: This used to call RemoveAt(0), which was an n^2 operation.  Removing from the end of the array now.
                for (int i = _size - 1; i >= 0; i--) { 
                    RemoveAt(i); 
                }
 
                if (_owner is INamingContainer)
                    _owner.ClearNamingContainer();
            }
        } 

 
        ///  
        ///    
        ///       Indicates whether the collection contains a specific object 
        ///    
        /// 
        public virtual bool Contains(Control c) {
            if (_controls == null || c == null) 
                return false;
 
            for (int i = 0; i < _size; i++) { 
                if (Object.ReferenceEquals(c, _controls[i])) {
                    return true; 
                }
            }
            return false;
        } 

        /* 
         * Retrieves the number of child controls. 
         */
 
        /// 
        ///    
        ///       Gets the number of child controls in the collection.
        ///     
        /// 
        public virtual int Count { 
            get { 
                return _size;
            } 
        }


        ///  
        ///    [To be supplied.]
        ///  
        protected Control Owner { 
            get {
                return _owner; 
            }
        }

 
        /// 
        ///     
        ///       Returns the index of a specified  
        ///       object
        ///       in the collection. 
        ///    
        /// 
        public virtual int IndexOf(Control value) {
            if (_controls == null) 
                return -1;
 
            return Array.IndexOf(_controls, value, 0, _size); 
        }
 

        /// 
        ///    
        ///       Returns an enumerator of all controls in the collection. 
        ///    
        ///  
        public virtual IEnumerator GetEnumerator() { 
            return new ControlCollectionEnumerator(this);
        } 


        /// 
        ///    Copies the specified child control to a location in the collection. 
        /// 
        public virtual void CopyTo(Array array, int index) { 
            if (_controls == null) 
                return;
            if ((array != null) && (array.Rank != 1)) 
                throw new HttpException(SR.GetString(SR.InvalidArgumentValue, "array"));

            Array.Copy(_controls, 0, array, index, _size);
        } 

 
        ///  
        ///    Gets the parent control of the control collection.
        ///  
        public Object SyncRoot {
            get { return this;}
        }
 

        ///  
        ///    Gets a value indicating whether the collection is read-only. 
        /// 
        public bool IsReadOnly { 
            get { return (_readOnlyErrorMsg != null); }
        }

        // Setting an error message makes the control collection read only.  If the user tries to modify 
        // the collection, we look up the error message in the resources and throw an exception.
        // Set errorMsg to null to make the collection not read only. 
        internal string SetCollectionReadOnly(string errorMsg) { 
            string olderror = _readOnlyErrorMsg;
            _readOnlyErrorMsg = errorMsg; 
            return olderror;
        }

 
        /// 
        ///     Gets a value indicating whether the collection 
        ///       is synchronized. 
        /// 
        public bool IsSynchronized { 
            get { return false;}
        }

 

        ///  
        ///     
        ///       Gets a reference to an ordinal-indexed control in the collection.
        ///     
        /// 
        virtual public Control this[int index]
        {
            get { 
                if (index < 0 || index >= _size) {
                    throw new ArgumentOutOfRangeException("index"); 
                } 
                return _controls[index];
            } 
        }


        ///  
        ///    
        ///       Removes the specified child control from the collection. 
        ///     
        /// 
        public virtual void RemoveAt(int index) { 

            if (_readOnlyErrorMsg != null) {
                throw new HttpException(SR.GetString(_readOnlyErrorMsg ));
            } 

            Control child = this[index]; 
            _size--; 
            if (index < _size) {
                Array.Copy(_controls, index + 1, _controls, index, _size - index); 
            }
            _controls[_size] = null;
            _version++;
            _owner.RemovedControl(child); 

        } 
 

        ///  
        ///    
        ///       Removes the specified
        ///       child control object from the collection.
        ///     
        /// 
        public virtual void Remove(Control value) { 
            int index = IndexOf(value); 
            if (index >=0)
                RemoveAt(index); 
        }

        // This is a copy of the ArrayListEnumeratorSimple in ArrayList.cs
        private class ControlCollectionEnumerator : IEnumerator 
        {
            private ControlCollection list; 
            private int index; 
            private int version;
            private Control currentElement; 

            internal ControlCollectionEnumerator(ControlCollection list) {
                this.list = list;
                this.index = -1; 
                version = list._version;
            } 
 
            public bool MoveNext() {
                if (index < (list.Count-1)) { 
                    if (version != list._version) {
                        throw new InvalidOperationException(SR.GetString(SR.ListEnumVersionMismatch));
                    }
 
                    index++;
                    currentElement = list[index]; 
                    return true; 
                }
                else 
                    index = list.Count;
                return false;
            }
 
            object IEnumerator.Current {
                get { 
                    return Current; 
                }
            } 

            public Control Current {
                get {
                    if (index == -1) 
                        throw new InvalidOperationException(SR.GetString(SR.ListEnumCurrentOutOfRange));
                    if (index >= list.Count) 
                        throw new InvalidOperationException(SR.GetString(SR.ListEnumCurrentOutOfRange)); 
                    return currentElement;
                } 
            }

            public void Reset() {
                if (version != list._version) 
                    throw new InvalidOperationException(SR.GetString(SR.ListEnumVersionMismatch));
                currentElement = null; 
                index = -1; 
            }
        } 

    }
}

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