SearchExpression.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 / SearchExpression.cs / 1305376 / SearchExpression.cs
                        

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

    public class SearchExpression : ParameterDataSourceExpression { 
        public string DataFields { 
            get {
                return (string)ViewState["DataFields"] ?? String.Empty; 
            }
            set {
                ViewState["DataFields"] = value;
            } 
        }
 
        public SearchType SearchType { 
            get {
                object o = ViewState["SearchType"]; 
                return o != null ? (SearchType)o : SearchType.StartsWith;
            }
            set {
                ViewState["SearchType"] = value; 
            }
        } 
 
        public StringComparison ComparisonType {
            get { 
                object o = ViewState["ComparisonType"];
                return o != null ? (StringComparison)o : StringComparison.OrdinalIgnoreCase;
            }
            set { 
                ViewState["ComparisonType"] = value;
            } 
        } 

        public override IQueryable GetQueryable(IQueryable source) { 
            if (source == null) {
                return null;
            }
 
            if ((DataFields == null) || String.IsNullOrEmpty(DataFields.Trim())) {
                throw new InvalidOperationException(AtlasWeb.Expressions_DataFieldRequired); 
            } 

            IDictionary values = GetValues(); 

            if (values.Count == 0) {
                throw new InvalidOperationException(AtlasWeb.SearchExpression_ParameterRequired);
            } 

            string query = Convert.ToString(values.First().Value, CultureInfo.CurrentCulture); 
 
            if (String.IsNullOrEmpty(query)) {
                return null; 
            }

            string[] properties = DataFields.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 
            // Use the or expression to or the fields together
            List searchExpressions = new List(); 
 
            ParameterExpression parameterExpression = Expression.Parameter(source.ElementType, String.Empty);
 
            foreach (string p in properties) {
                Expression property = ExpressionHelper.CreatePropertyExpression(parameterExpression, p.Trim());
                searchExpressions.Add(CreateCallExpression(property, query));
            } 

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

        private Expression CreateCallExpression(Expression property, string query) {
            // LINQ to SQL does not support the overloads StartsWith(string, StringComparer) or EndsWith(string, StringComparer)
            // and Contains has not overload that takes a StringComparer 
            if (SearchType == SearchType.Contains || (ViewState["ComparisonType"] == null)) {
                return Expression.Call(property, SearchType.ToString(), Type.EmptyTypes, Expression.Constant(query, property.Type)); 
            } 
            return Expression.Call(property, SearchType.ToString(), Type.EmptyTypes, Expression.Constant(query, property.Type), Expression.Constant(ComparisonType));
        } 
    }

}

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

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