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namespace System.Web.UI.WebControls.Expressions {
using System;
using System.Collections.Generic;
using System.Security.Permissions;
using System.Web.UI;
using System.Linq.Expressions;
using System.Linq;
public class PropertyExpression : ParameterDataSourceExpression {
public override IQueryable GetQueryable(IQueryable source) {
if (source == null) {
return null;
}
IDictionary<string, object> values = GetValues();
List<Expression> equalsExpressions = new List<Expression>();
ParameterExpression parameterExpression = Expression.Parameter(source.ElementType, String.Empty);
foreach (KeyValuePair<string, object> pair in values) {
if (!String.IsNullOrEmpty(pair.Key)) {
// Create the property expression
Expression property = ExpressionHelper.CreatePropertyExpression(parameterExpression, pair.Key);
// Get the value
object value = ExpressionHelper.BuildObjectValue(pair.Value, property.Type);
// Create Property == Value and '&&' the expressions together
if (value != null) {
Expression valueExpression = Expression.Constant(value, property.Type);
Expression equalsExpression = Expression.Equal(property, valueExpression);
equalsExpressions.Add(equalsExpression);
}
}
}
if (equalsExpressions.Any()) {
Expression body = ExpressionHelper.And(equalsExpressions);
return ExpressionHelper.Where(source, Expression.Lambda(body, parameterExpression));
}
return source;
}
}
}
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