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