TypeConverterHelper.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Shared / System / Windows / Media / TypeConverterHelper.cs / 1 / TypeConverterHelper.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//  Microsoft Avalon
//  Copyright (c) Microsoft Corporation, All rights reserved.
//
//  File:       TypeConverterHelper.cs 
//
//----------------------------------------------------------------------------- 
using System; 
using System.Diagnostics;
using System.ComponentModel; 
using System.Windows.Markup;
using System.Runtime.InteropServices;
using System.Windows.Navigation;
 
namespace System.Windows.Media
{ 
    #region UriHolder 

    ///  
    /// UriHolder
    /// Holds Original and Base Uris
    /// 
    [StructLayout(LayoutKind.Sequential, Pack=1)] 
    internal struct UriHolder
    { 
 
        /// 
        /// BaseUri 
        /// Can be null
        /// 
        internal Uri BaseUri;
 
        /// 
        /// OriginalUri 
        ///  
        internal Uri OriginalUri;
    }; 

    #endregion

    #region TypeConverterHelper 

    ///  
    ///     This helper method is used primarily by type converters to resolve their uri 
    /// 
    ///  
    ///     There are three scenarios that can happen:
    ///
    ///     1) inputString is an absolute uri -- we return it as the resolvedUri
    ///     2) inputString is not absolute: 
    ///         i) the relativeBaseUri (obtained from IUriContext) has the following values:
    ///                 a) is an absolute uri, we use relativeBaseUri as base uri and resolve 
    ///                 the inputString against it 
    ///
    ///                 b) is a relative uri, we use Application's base uri (obtained from 
    ///                 BindUriHelperCore.BaseUri) as the base and resolve the relativeBaseUri
    ///                 against it; furthermore, we resolve the inputString against with uri
    ///                 obtained from the application base resolution.
    /// 
    ///                 c) is "", we resolve inputString against the Application's base uri
    ///  
    internal static class TypeConverterHelper 
    {
        internal static UriHolder GetUriFromUriContext(ITypeDescriptorContext context, object inputString) 
        {
            UriHolder uriHolder = new UriHolder();

            if (inputString is string) 
            {
                uriHolder.OriginalUri = new Uri((string)inputString, UriKind.RelativeOrAbsolute); 
            } 
            else
            { 
                Debug.Assert(inputString is Uri);
                uriHolder.OriginalUri = (Uri)inputString;
            }
 
            if (uriHolder.OriginalUri.IsAbsoluteUri == false)
            { 
                //Debug.Assert (context != null, "Context should not be null"); 
                if (context != null)
                { 
                    IUriContext iuc = (IUriContext)context.GetService(typeof(IUriContext));

                    //Debug.Assert (iuc != null, "IUriContext should not be null here");
                    if (iuc != null) 
                    {
                        // the base uri is NOT "" 
                        if (iuc.BaseUri != null) 
                        {
 
                            uriHolder.BaseUri = iuc.BaseUri;

                            if (!uriHolder.BaseUri.IsAbsoluteUri)
                            { 
                                uriHolder.BaseUri = new Uri(BaseUriHelper.BaseUri, uriHolder.BaseUri);
                            } 
                        } // uriHolder.BaseUriString != "" 
                        else
                        { 
                            // if we reach here, the base uri we got from IUriContext is ""
                            // and the inputString is a relative uri.  Here we resolve it to
                            // application's base
                            uriHolder.BaseUri = BaseUriHelper.BaseUri; 
                        }
                    } // iuc != null 
                } // context!= null 
            } // uriHolder.OriginalUri.IsAbsoluteUri == false
 
            return uriHolder;
        }
    }
 
#endregion
} 

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

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