X is a variable but used like a type when trying to cast

I have the following code. I am passing a string of the name of the entity type I want to query and getting the type based on the string. I want to get the DbSet back and return an IQueryable. The problem is where I am doing (DbSet< tableEntity >) and getting the following error: ta"bleEntity is a variable but used like a type" when trying to cast. Is there a way to resolve this?

public object GetList(string tableEntity)
{
    Type tableEntity = Type.GetType("TestProject." + typeName
 + ", TestProject");

    var dbObject = (DbSet<tableEntity>)typeof(DbContext).GetMethod("Set", Type.EmptyTypes)
                        .MakeGenericMethod(tableEntity)
                        .Invoke(databaseContext, null);

    return dbObject.AsQueryable();            
}