Helper class to achieve common task

Question

I would like to create a helper class to do some common task.

For example, I am retrieving some results from Database and then assigning the values to variables. Bu

Answer 1

A more radical approach (which would remove the issue) would be to eradicate NULLs from your values altogether.

The simplest way would be through ISNULL() when you query your database:

Where now you do

SELECT MyColumn FROM MyTable

You instead go

SELECT ISNULL(MyColumn, '') AS MyColumn FROM MyTable

Then you can assume no NULLs will get through to your code.

Answer 2

Well what you are trying to acchieve is to avoid the NullReferenceException i guess.

You could achieve this by writing a generic method like this

public static TValue GetValueSafe<TValue,TObject>(TObject obj, Func<TObject,TValue> accessor)
{
    if(obj== null)
        return default(TValue);

    return accessor(obj);
}

Then use it like this:

string strValue = Helpers.GetValueSafe(dr[colName], o => o.toString());

This would either return the value of toString, or if dr[colName] == null returns default(string) which is null.

You could exand this by adding a defaultParameter to define a value on "failure".

However i would'nt recommend using this.