45 lines
1.6 KiB
C#
45 lines
1.6 KiB
C#
using System.Collections.Generic;
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using System.Linq.Expressions;
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namespace Hncore.Infrastructure.EntitiesExtension
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{
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public class ParameterRebinder : ExpressionVisitor
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{
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private readonly Dictionary<ParameterExpression, ParameterExpression> map;
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/// <summary>
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/// Default construcotr
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/// </summary>
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/// <param name="map">Map specification</param>
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public ParameterRebinder(Dictionary<ParameterExpression, ParameterExpression> map)
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{
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this.map = map ?? new Dictionary<ParameterExpression, ParameterExpression>();
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}
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/// <summary>
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/// Replate parameters in expression with a Map information
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/// </summary>
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/// <param name="map">Map information</param>
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/// <param name="exp">Expression to replace parameters</param>
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/// <returns>Expression with parameters replaced</returns>
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public static Expression ReplaceParameters(Dictionary<ParameterExpression, ParameterExpression> map, Expression exp)
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{
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return new ParameterRebinder(map).Visit(exp);
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}
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/// <summary>
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/// Visit pattern method
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/// </summary>
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/// <param name="p">A Parameter expression</param>
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/// <returns>New visited expression</returns>
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protected override Expression VisitParameter(ParameterExpression p)
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{
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ParameterExpression replacement;
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if (map.TryGetValue(p, out replacement))
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{
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p = replacement;
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}
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return base.VisitParameter(p);
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}
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}
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}
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