Custom LINQ Providers
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This document discusses querying data sources using IQueryProvider. It shows code for executing a query generically on a source and for creating a query by calling a generic method and passing the source expression and a predicate expression. It also compares different ways to check for string equality in C#, showing that s1 == s2, s1.Equals(s2), String.Equals(s1, s2), and String.Compare(s1, s2) == 0 all perform the same comparison.
![source
.Provider
.Execute<int>(
Expression.Call(null,
((MethodInfo) MethodBase
.GetCurrentMethod())
.MakeGenericMethod(
new Type[] {
typeof(TSource) }),
new Expression[] {source.Expression }));](https://image.slidesharecdn.com/vbaumlinqproviders-111023154602-phpapp02/85/Custom-LINQ-Providers-7-320.jpg)
![Source
.Provider
.CreateQuery<TSource>(
Expression.Call(
null,
((MethodInfo)
MethodBase
.GetCurrentMethod())
.MakeGenericMethod(
new Type[] { typeof(TSource) }),
new Expression[] {
source.Expression,
Expression.Quote(predicate) }));](https://image.slidesharecdn.com/vbaumlinqproviders-111023154602-phpapp02/85/Custom-LINQ-Providers-8-320.jpg)
Custom LINQ Providers
- 7. source .Provider .Execute<int>( Expression.Call(null, ((MethodInfo) MethodBase .GetCurrentMethod()) .MakeGenericMethod( new Type[] { typeof(TSource) }), new Expression[] {source.Expression }));
- 8. Source .Provider .CreateQuery<TSource>( Expression.Call( null, ((MethodInfo) MethodBase .GetCurrentMethod()) .MakeGenericMethod( new Type[] { typeof(TSource) }), new Expression[] { source.Expression, Expression.Quote(predicate) }));
- 10. IQUERY PROVIDER
- 11. IQUERY PROVIDER
- 14. //is it the same thing? s1 == s2 s1.Equals(s2) String.Equals(s1, s2) String.Compare(s1, s2) == 0