StringSource.cs source code in C# .NET

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                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / StringSource.cs / 1 / StringSource.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms { 
 
    using System.Runtime.InteropServices.ComTypes;
    using System.Runtime.InteropServices; 
    using System.Collections;
    using System.Diagnostics.CodeAnalysis;

 
    /// 
    ///  
    ///     
    ///       Represents an internal class that is used bu ComboBox and TextBox AutoCompleteCustomSoucr property.
    ///       This class is reponsible for initializing the SHAutoComplete COM object and setting options in it. 
    ///       The StringSource contains an array of Strings which is passed to the COM object as the custom source.
    ///    
    /// 
    internal class StringSource : IEnumString { 

        private string[] strings; 
        private int current; 
        private int size;
        private UnsafeNativeMethods.IAutoComplete2 autoCompleteObject2; 

        /// 
        /// 
        ///     
        ///       SHAutoComplete COM object CLSID.
        ///     
        ///  
        private static Guid   autoCompleteClsid = new Guid("{00BB2763-6A77-11D0-A535-00C04FD7D062}");
 
        /// 
        /// 
        ///    
        ///       Constructor. 
        ///    
        ///  
        public StringSource(string[] strings) { 
            Array.Clear(strings,0, size);
 
            if (strings != null) {
                this.strings = strings;
            }
            current = 0; 
            size = (strings == null ) ? 0 : strings.Length;
 
            Guid iid_iunknown = typeof(UnsafeNativeMethods.IAutoComplete2).GUID; 
            object obj = UnsafeNativeMethods.CoCreateInstance(ref autoCompleteClsid, null, NativeMethods.CLSCTX_INPROC_SERVER, ref iid_iunknown);
 
            autoCompleteObject2 = (UnsafeNativeMethods.IAutoComplete2)obj;
        }

        ///  
        /// 
        ///     
        ///       This is the method that binds the custom source with the IAutoComplete interface.The "hWndEdit" is the handle 
        ///       to the edit Control and the "options' are the options that need to be set in the AUTOCOMPLETE mode.
        ///     
        /// 
        public bool Bind(HandleRef edit, int options) {

            bool retVal = false; 

            if (autoCompleteObject2 != null) { 
                try 
                {
                    autoCompleteObject2.SetOptions(options); 
                    autoCompleteObject2.Init(edit, (IEnumString)this, null, null);
                    retVal = true;
                }
                catch 
                {
                    retVal = false; 
                } 
            }
            return retVal; 
        }
 	[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
        public void ReleaseAutoComplete()
        { 
            if (autoCompleteObject2 != null)
            { 
                Marshal.ReleaseComObject(autoCompleteObject2); 
                autoCompleteObject2 = null;
            } 
        }

        public void RefreshList(string[] newSource)
        { 
            Array.Clear(strings,0, size);
 
            if (strings != null) { 
                this.strings = newSource;
            } 
            current = 0;
            size = (strings == null ) ? 0 : strings.Length;
        }
 
        #region IEnumString Members
 
        void IEnumString.Clone(out IEnumString ppenum) 
        {
            ppenum = new StringSource(strings); 
        }

        int IEnumString.Next(int celt, string[] rgelt, IntPtr pceltFetched)
        { 
            if (celt < 0)
            { 
                return NativeMethods.E_INVALIDARG; 
            }
            int fetched = 0; 

            while (current < size && celt > 0)
            {
                rgelt[fetched] = strings[current]; 
                current++;
                fetched++; 
                celt--; 
            }
 
            if (pceltFetched != IntPtr.Zero)
            {
                Marshal.WriteInt32(pceltFetched, fetched);
            } 
            return celt == 0 ? NativeMethods.S_OK : NativeMethods.S_FALSE;
        } 
 
        void IEnumString.Reset()
        { 
            current = 0;
        }

        int IEnumString.Skip(int celt) 
        {
            current += celt; 
            if (current >= size) 
            {
                return (NativeMethods.S_FALSE); 
            }
            return NativeMethods.S_OK;
        }
 
        #endregion
    } 
} 


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

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