49 lines
1.6 KiB
C#
49 lines
1.6 KiB
C#
|
using System;
|
|||
|
|
using System.Collections.Generic;
|
|||
|
|
using System.Linq;
|
|||
|
|
using System.Text;
|
|||
|
|
using System.Linq.Expressions;
|
|||
|
|
|
|||
|
|
namespace MyCode.Project.Infrastructure
|
|||
|
|
{
|
|||
|
|
/// <summary>
|
|||
|
|
/// Represents the parameter rebinder used for rebinding the parameters
|
|||
|
|
/// for the given expressions. This is part of the solution which solves
|
|||
|
|
/// the expression parameter problem when going to Entity Framework by using
|
|||
|
|
/// Apworks specifications. For more information about this solution please
|
|||
|
|
/// refer to http://blogs.msdn.com/b/meek/archive/2008/05/02/linq-to-entities-combining-predicates.aspx.
|
|||
|
|
/// </summary>
|
|||
|
|
internal class ParameterRebinder : ExpressionVisitor
|
|||
|
|
{
|
|||
|
|
#region Private Fields
|
|||
|
|
private readonly Dictionary<ParameterExpression, ParameterExpression> map;
|
|||
|
|
#endregion
|
|||
|
|
|
|||
|
|
#region Ctor
|
|||
|
|
internal ParameterRebinder(Dictionary<ParameterExpression, ParameterExpression> map)
|
|||
|
|
{
|
|||
|
|
this.map = map ?? new Dictionary<ParameterExpression, ParameterExpression>();
|
|||
|
|
}
|
|||
|
|
#endregion
|
|||
|
|
|
|||
|
|
#region Internal Static Methods
|
|||
|
|
internal static Expression ReplaceParameters(Dictionary<ParameterExpression, ParameterExpression> map, Expression exp)
|
|||
|
|
{
|
|||
|
|
return new ParameterRebinder(map).Visit(exp);
|
|||
|
|
}
|
|||
|
|
#endregion
|
|||
|
|
|
|||
|
|
#region Protected Methods
|
|||
|
|
protected override Expression VisitParameter(ParameterExpression p)
|
|||
|
|
{
|
|||
|
|
ParameterExpression replacement;
|
|||
|
|
if (map.TryGetValue(p, out replacement))
|
|||
|
|
{
|
|||
|
|
p = replacement;
|
|||
|
|
}
|
|||
|
|
return base.VisitParameter(p);
|
|||
|
|
}
|
|||
|
|
#endregion
|
|||
|
|
}
|
|||
|
|
}
|