I'm looking for way to get something like this:
string _col1 = "first name";
string _name;
var query = from c in ctx.Customers select c;
_name = query.FirstOrDefault().[_name];
As far as I can see I can only get strongly typed field names but I would like to provide them as string variables.
I'm not sure if EF provides you with a way to get a property value based on the string name of the property, but you can use reflection.
string name = typeof(Customer)
.GetProperty("first name")
.GetValue(query.First(), null) as string;
I'm guessing the EF class you're dealing with is called Customer.
You need to use reflection for this. If you are trying to filter by a dynamicly selected column, you can try something like this:
string propertyName
string keyword
ParameterExpression parameter = Expression.Parameter(typeof(YourType), "x");
Expression property = Expression.Property(parameter, propertyName);
Expression target = Expression.Constant(keyword);
Expression containsMethod = Expression.Call(property, "Contains", null, target);
Expression<Func<YourType, bool>> lambda =
Expression.Lambda<Func<YourType, bool>>(containsMethod, parameter);
var companies = repository.AsQueryable().Where(lambda);
I what you are trying to do is selecting a particular column, then you can use the same principle for generating the lamba expression and using it in the select (minus the condition)
var companies = repository.AsQueryable().Where(whatever).Select(lambda);
x => x.Property it could be anything. The reference, I got from a question I asked, stackoverflow.com/questions/7246715/….For some kind of reason it won't work for me.
That's my similar working solution:
string name = null;
// Select the PropertyInfo of the column.
PropertyInfo propertyInfo = query.First().GetType().GetProperty("first name");
if (propertyInfo != null)
{
try
{
// Select the content of the column.
name = pi.GetValue(query.First(), null).ToString();
}
catch (Exception)
{
// Continue with null-string.
}
}
