RangeExpression.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 / xsp / System / Extensions / UI / WebControls / Expressions / RangeExpression.cs / 1305376 / RangeExpression.cs
                        

                        
                            #if ORYX_VNEXT 
namespace Microsoft.Web.Data.UI.WebControls.Expressions {
    using System.Web;
#else
namespace System.Web.UI.WebControls.Expressions { 
#endif
    using System; 
    using System.Collections; 
    using System.Collections.Generic;
    using System.Collections.Specialized; 
    using System.ComponentModel;
    using System.Diagnostics;
    using System.Linq;
    using System.Linq.Expressions; 
    using System.Web.Resources;
    using System.Web.UI; 
    using System.Web.UI.WebControls; 

    public class RangeExpression : ParameterDataSourceExpression { 
        public string DataField {
            get {
                return (string)ViewState["DataField"] ?? String.Empty;
            } 
            set {
                ViewState["DataField"] = value; 
            } 
        }
 
        public RangeType MinType {
            get {
                object o = ViewState["MinType"];
                return o != null ? (RangeType)o : RangeType.None; 
            }
            set { 
                ViewState["MinType"] = value; 
            }
        } 

        public RangeType MaxType {
            get {
                object o = ViewState["MaxType"]; 
                return o != null ? (RangeType)o : RangeType.None;
            } 
            set { 
                ViewState["MaxType"] = value;
            } 
        }

        internal virtual new IOrderedDictionary GetValues() {
            return Parameters.GetValues(Context, Owner); 
        }
 
        public override IQueryable GetQueryable(IQueryable source) { 
            if (source == null) {
                return null; 
            }

            if (String.IsNullOrEmpty(DataField)) {
                throw new InvalidOperationException(AtlasWeb.Expressions_DataFieldRequired); 
            }
 
            IOrderedDictionary values = GetValues(); 
            ParameterExpression parameterExpression = Expression.Parameter(source.ElementType, String.Empty);
            Expression properyExpression = ExpressionHelper.GetValue(ExpressionHelper.CreatePropertyExpression(parameterExpression, DataField)); 

            if (MinType == RangeType.None && MaxType == RangeType.None) {
                throw new InvalidOperationException(AtlasWeb.RangeExpression_RangeTypeMustBeSpecified);
            } 

            Expression minExpression = null; 
            Expression maxExpression = null; 

            if (MinType != RangeType.None) { 
                if (values.Count == 0) {
                    throw new InvalidOperationException(AtlasWeb.RangeExpression_MinimumValueRequired);
                }
 
                if (values[0] != null) {
                    minExpression = GetMinRangeExpression(properyExpression, values[0], MinType); 
                } 
            }
 
            if (MaxType != RangeType.None) {
                if (values.Count == 0  || ((minExpression != null) && (values.Count == 1))) {
                    throw new InvalidOperationException(AtlasWeb.RangeExpression_MaximumValueRequired);
                } 

                object maxValue = minExpression == null ? values[0] : values[1]; 
                if (maxValue != null) { 
                    maxExpression = GetMaxRangeExpression(properyExpression, maxValue, MaxType);
                } 
            }

            if ((maxExpression == null) && (minExpression == null)) {
                return null; 
            }
 
            Expression rangeExpression = CreateRangeExpressionBody(minExpression, maxExpression); 

            return ExpressionHelper.Where(source, Expression.Lambda(rangeExpression, parameterExpression)); 
        }

        private static Expression GetMinRangeExpression(Expression propertyExpression, object value, RangeType rangeType) {
            ConstantExpression constantValue = Expression.Constant(ExpressionHelper.BuildObjectValue(value, propertyExpression.Type)); 
            switch (rangeType) {
                case RangeType.Exclusive: 
                    return Expression.GreaterThan(propertyExpression, constantValue); 
                case RangeType.None:
                    return null; 
                case RangeType.Inclusive:
                    return Expression.GreaterThanOrEqual(propertyExpression, constantValue);
                default:
                    Debug.Fail("shouldn't get here!"); 
                    return null;
            } 
        } 

        private static Expression GetMaxRangeExpression(Expression propertyExpression, object value, RangeType rangeType) { 
            ConstantExpression constantValue = Expression.Constant(ExpressionHelper.BuildObjectValue(value, propertyExpression.Type));
            switch (rangeType) {
                case RangeType.Exclusive:
                    return Expression.LessThan(propertyExpression, constantValue); 
                case RangeType.None:
                    return null; 
                case RangeType.Inclusive: 
                    return Expression.LessThanOrEqual(propertyExpression, constantValue);
                default: 
                    Debug.Fail("shouldn't get here!");
                    return null;
            }
        } 

        private static Expression CreateRangeExpressionBody(Expression minExpression, Expression maxExpression) { 
            if (minExpression == null && maxExpression == null) { 
                return null;
            } 

            if (minExpression == null) {
                return maxExpression;
            } 

            if (maxExpression == null) { 
                return minExpression; 
            }
 
            return Expression.AndAlso(minExpression, maxExpression);
        }
    }
} 

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

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