LINQ Expression<Func<T, bool>> equavalent of .Contains()
linq, linq-expressions
Solution
public static Expression<Func<string, bool>> StringContains(string subString)
{
MethodInfo contains = typeof(string).GetMethod("Contains");
ParameterExpression param = Expression.Parameter(typeof(string), "s");
var call = Expression.Call(param, contains, Expression.Constant(subString, typeof(string)));
return Expression.Lambda<Func<string, bool>>(call, param);
}
...
// s => s.Contains("hello")
Expression<Func<string, bool>> predicate = StringContains("hello");
Looking at this many years later, I suddenly realize there's a much simpler approach for this specific example:
Expression<Func<string, bool>> predicate = s => s.Contains("hello");
Problem
Has anybody got an idea of how to create a .Contains(string) function using Linq Expressions, or even create a predicate to accomplish this ``` public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2) { var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>()); return Expression.Lambda<Func<T, bool>> (Expression.OrElse(expr1.Body, invokedExpr), expr1.Parameters); } ``` Something simular to this would be ideal?