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C# Generate Expression to Select with Where
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| private IQueryable<T> WhereEqual<T>(IQueryable query, string prop, object param) | |
| { | |
| var select = Expression.Parameter(typeof(T), "select"); | |
| MemberExpression property = null; | |
| foreach (var node in prop.Split('.')) | |
| { | |
| property = property == null | |
| ? Expression.Property(select, node) | |
| : Expression.Property(property, node); | |
| } | |
| var expression = Expression.Equal(property, Expression.Constant(param)); | |
| var where = Expression.Call( | |
| typeof(Queryable), | |
| "Where", | |
| new[] { query.ElementType }, | |
| query.Expression, | |
| Expression.Lambda<Func<T, bool>>(expression, select)); | |
| return query.Provider.CreateQuery<T>(where); | |
| } | |
| /* Usage: | |
| * | |
| * var query = from customer in customers select new Wrapper { Customer = customer }; | |
| * query = WhereEqual<Wrapper>(query, "Customer.Id", id); | |
| */ |
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