Here is a sample program to build Dynamic queries to query List<> with Where condition
C# Code:
Reference: MSDN
C# Code:
static void Main(string[] args)
{
IQueryable<Country> queryableData = GetCountries().AsQueryable();
ParameterExpression pe = Expression.Parameter(typeof(Country));
MemberExpression me = Expression.PropertyOrField(pe, "Id");
ConstantExpression cex = Expression.Constant(10, typeof(int));
BinaryExpression be = Expression.LessThan(me, cex);
MethodCallExpression whereCallExpression = Expression.Call(
typeof(Queryable),
"Where",
new Type[] { queryableData.ElementType },
queryableData.Expression,
Expression.Lambda<Func<Country, bool>>(be, pe));
IQueryable<Country> results = queryableData.Provider.CreateQuery<Country>(whereCallExpression);
foreach (var item in results)
{
Console.Write(item.Id);
Console.Write(" : ");
Console.WriteLine(item.Name);
}
Console.ReadLine();
}
public static List<Country> GetCountries()
{
// To get the country list in c# check my previous post Click Here
// i have added a Id property to the above link sample to make some condition work in this post
}
class Country
{
public Int32 Id { get; set; }
public string Code { get; set; }
public string Name { get; set; }
}
Reference: MSDN
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