DataMemberConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / MIT / System / Web / UI / MobileControls / Design / Converters / DataMemberConverter.cs / 1305376 / DataMemberConverter.cs
                        

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

namespace System.Web.UI.Design.MobileControls.Converters 
{ 
    using System;
    using System.Collections; 
    using System.ComponentModel;
    using System.ComponentModel.Design;
    using System.Data;
    using System.Diagnostics; 
    using System.Globalization;
    using System.Runtime.InteropServices; 
    using System.Web.UI.Design; 
    using System.Security.Permissions;
 
    /// 
    /// 
    ///    
    ///       Provides design-time support for a component's DataMember properties. 
    ///    
    ///  
    [ 
        System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.Demand,
        Flags=System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode) 
    ]
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [Obsolete("The System.Web.Mobile.dll assembly has been deprecated and should no longer be used. For information about how to develop ASP.NET mobile applications, see http://go.microsoft.com/fwlink/?LinkId=157231.")] 
    public class DataMemberConverter : TypeConverter
    { 
 
        /// 
        ///  
        ///    
        ///       Initializes a new instance of .
        ///    
        ///  
        public DataMemberConverter()
        { 
        } 

        ///  
        /// 
        ///    
        ///       Gets a value indicating whether this converter can
        ///       convert an object in the given source type to the native type of the converter 
        ///       using the context.
        ///     
        ///  
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        { 
            if (sourceType == typeof(string))
            {
                return true;
            } 
            return false;
        } 
 
        /// 
        ///  
        ///    
        ///       Converts the given object to the converter's native type.
        ///    
        ///  
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        { 
            if (value == null) 
            {
                return String.Empty; 
            }
            else if (value.GetType() == typeof(string))
            {
                return (string)value; 
            }
            throw GetConvertFromException(value); 
        } 

        ///  
        /// 
        ///    
        ///       Gets the fields present within the selected data source if information about them is available.
        ///     
        /// 
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) 
        { 
            string[] names = null;
 
            if (context != null)
            {
                IComponent component = context.Instance as IComponent;
                if (component is IDeviceSpecificChoiceDesigner) 
                {
                    component = ((IDeviceSpecificChoiceDesigner)component).UnderlyingControl; 
                } 

                if (component != null) 
                {
                    ISite componentSite = component.Site;
                    if (componentSite != null)
                    { 
                        IDesignerHost designerHost = (IDesignerHost)componentSite.GetService(typeof(IDesignerHost));
                        if (designerHost != null) 
                        { 
                            IDesigner designer = designerHost.GetDesigner(component);
 
                            if (designer is IDataSourceProvider)
                            {
                                object dataSource = ((IDataSourceProvider)designer).GetSelectedDataSource();
 
                                if (dataSource != null)
                                { 
                                    names = DesignTimeData.GetDataMembers(dataSource); 
                                }
                            } 
                        }
                    }
                }
 
                if (names == null)
                { 
                    names = new string[0]; 
                }
                Array.Sort(names); 
            }
            return new StandardValuesCollection(names);
        }
 
        /// 
        ///  
        ///     
        ///       Gets a value indicating whether the collection of standard values returned from
        ///     is an exclusive 
        ///       list of possible values, using the specified context.
        ///    
        /// 
        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) 
        {
            return false; 
        } 

        ///  
        /// 
        ///    
        ///       Gets a value indicating whether this object supports a standard set of values
        ///       that can be picked from a list. 
        ///    
        ///  
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) 
        {
            if (context.Instance is IComponent) 
            {
                // We only support the dropdown in single-select mode.
                return true;
            } 
            return false;
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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