How can I read string value and store it in a array using data reader

Question

I am reading some list of values in the result but I am not sure where I am going wrong, I wont know the array size so I cant assign any value to it

string[] result = null;
while (reader.Read())
{
    result = Convert.ToString[](reader["RoleID"]);
}
reader.Close();

I am getting: Syntax error; value expected.

After I get the result value, how can I compare the values inside the result with a string? For example, I want to check whether the string check="Can send message"; is present in the result array or not. How can I do that?

Answer 1

Your code is syntactically wrong, hence the error. But when you have to build a collection of items but you do not know the size in advance, you want to use a List<T> as opposed to an array. The list will allow you to keep adding items.

var results = new List<string>();
while (reader.Read())
{
    results.Add(reader["RoleID"].ToString());
}

// results now holds all of the RoleID values in the reader 

You can access the elements of the list via index, just like an array, and can query the list using Linq (also just like an array) if needed.

string check = "something";
if (results.Any(item => item.Equals(check)))
{
    // results contains the value in check 
}

// or use all items that equal check
foreach (var item in results.Where(obj => obj.Equals(check))
{
    // do something with each item that equals check
}