DataErrorValidationRule.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Controls / DataErrorValidationRule.cs / 1305600 / DataErrorValidationRule.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) by Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: 
//      DataErrorValidationRule is used when a ValidationError is the result of
//      a data error in the source item itself (e.g. as exposed by IDataErrorInfo). 
//
//---------------------------------------------------------------------------

 
using System;
using System.Collections; 
using System.ComponentModel; 
using System.Diagnostics;
using System.Globalization; 
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using MS.Internal; 

namespace System.Windows.Controls 
{ 
    /// 
    ///     DataErrorValidationRule can be added to the ValidationRulesCollection of a Binding 
    ///     or MultiBinding to indicate that data errors in the source object should
    ///     be considered ValidationErrors
    /// 
    public sealed class DataErrorValidationRule : ValidationRule 
    {
        ///  
        /// DataErrorValidationRule ctor. 
        /// 
        public DataErrorValidationRule() : base(ValidationStep.UpdatedValue, true) 
        {
        }

        ///  
        /// Validate is called when Data binding is updating
        ///  
        public override ValidationResult Validate(object value, CultureInfo cultureInfo) 
        {
            // This rule is called during the CommittedValue step, so the value is the 
            // owner of the rule collection - either a BindingGroup or an individual
            // binding expression.
            BindingGroup bindingGroup;
            BindingExpression bindingExpr; 

            if ((bindingGroup = value as BindingGroup) != null) 
            { 
                // in a BindingGroup, check the item-level IDataErrorInfo for each
                // source item in the group 
                IList items = bindingGroup.Items;
                for (int i=items.Count-1; i>=0; --i)
                {
                    IDataErrorInfo idei = items[i] as IDataErrorInfo; 
                    if (idei != null)
                    { 
                        string error = idei.Error; 
                        if (!String.IsNullOrEmpty(error))
                        { 
                            return new ValidationResult(false, error);
                        }
                    }
                } 
            }
            else if ((bindingExpr = value as BindingExpression) != null) 
            { 
                // in a binding, check the error info for the binding's source
                // property 
                IDataErrorInfo idei = bindingExpr.SourceItem as IDataErrorInfo;
                string name = (idei != null) ? bindingExpr.SourcePropertyName : null;

                if (!String.IsNullOrEmpty(name)) 
                {
                    // get the data error information, if any, by calling idie[name]. 
                    // We do this in a paranoid way, even though indexers with 
                    // string-valued arguments are not supposed to throw exceptions.
 
                    // PreSharp uses message numbers that the C# compiler doesn't know about.
                    // Disable the C# complaints, per the PreSharp documentation.
                    #pragma warning disable 1634, 1691
 
                    // PreSharp complains about catching NullReference (and other) exceptions.
                    // It doesn't recognize that IsCritical[Application]Exception() handles these correctly. 
                    #pragma warning disable 56500 

                    string error; 
                    try
                    {
                        error = idei[name];
                    } 
                    catch (Exception ex)
                    { 
                        if (CriticalExceptions.IsCriticalApplicationException(ex)) 
                            throw;
 
                        error = null;

                        if (TraceData.IsEnabled)
                        { 
                            TraceData.Trace(TraceEventType.Error,
                                            TraceData.DataErrorInfoFailed( 
                                                name, 
                                                idei.GetType().FullName,
                                                ex.GetType().FullName, 
                                                ex.Message),
                                            bindingExpr);
                        }
                    } 
                    #pragma warning restore 56500
                    #pragma warning restore 1634, 1691 
 
                    if (!String.IsNullOrEmpty(error))
                    { 
                        return new ValidationResult(false, error);
                    }
                }
            } 
            else
                throw new InvalidOperationException(SR.Get(SRID.ValidationRule_UnexpectedValue, this, value)); 
 
            return ValidationResult.ValidResult;
        } 

        internal static readonly DataErrorValidationRule Instance = new DataErrorValidationRule();
    }
} 


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

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