DataSourceConverter.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Designer / WebForms / System / Web / UI / Design / DataSourceConverter.cs / 1 / DataSourceConverter.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI.Design { 
 
    using System;
    using System.CodeDom; 
    using System.Collections;
    using System.ComponentModel;
    using System.ComponentModel.Design;
    using System.Data; 
    using System.Diagnostics;
    using System.Runtime.InteropServices; 
    using System.Globalization; 

    ///  
    /// 
    ///    
    ///       Provides design-time support for a component's data source property.
    ///     
    /// 
    [System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.Demand, Flags=System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode)] 
    public class DataSourceConverter : TypeConverter { 

        ///  
        /// 
        ///    
        ///       Initializes a new instance of .
        ///     
        /// 
        public DataSourceConverter() { 
        } 

        ///  
        /// 
        ///    
        ///       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 standard data sources accessible to the control. 
        ///    
        ///  
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) {
            object[] names = null;

            if (context != null) { 
                ArrayList list = new ArrayList();
 
                IContainer cont = context.Container; 
                if (cont != null) {
                    ComponentCollection objs = cont.Components; 

                    foreach (IComponent comp in (IEnumerable)objs) {
                        if (IsValidDataSource(comp) && !Marshal.IsComObject(comp)) {
 
                            PropertyDescriptor modifierProp = TypeDescriptor.GetProperties(comp)["Modifiers"];
                            if (modifierProp != null) { 
                                MemberAttributes modifiers = (MemberAttributes)modifierProp.GetValue(comp); 
                                if ((modifiers & MemberAttributes.AccessMask) == MemberAttributes.Private) {
                                    // must be declared as public or protected 
                                    continue;
                                }
                            }
 
                            ISite site = comp.Site;
                            if (site != null) { 
                                string name = site.Name; 
                                if (name != null) {
                                    list.Add(name); 
                                }
                            }
                        }
                    } 
                }
 
                names = list.ToArray(); 
                Array.Sort(names, Comparer.Default);
            } 
            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) {
            return true; 
        } 

        protected virtual bool IsValidDataSource(IComponent component) { 
            return (component is IEnumerable) || (component is IListSource);
        }
    }
} 


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

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